Initial commit

.gitignore

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+.pio
+.vscode/.browse.c_cpp.db*
+.vscode/c_cpp_properties.json
+.vscode/launch.json
+.vscode/ipch

.vscode/extensions.json

@@ -0,0 +1,10 @@
+{
+    // See http://go.microsoft.com/fwlink/?LinkId=827846
+    // for the documentation about the extensions.json format
+    "recommendations": [
+        "platformio.platformio-ide"
+    ],
+    "unwantedRecommendations": [
+        "ms-vscode.cpptools-extension-pack"
+    ]
+}

README.md

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+## About RippleCore
+
+RippleCore is a portable C++ library which provides classes for adding multi-hop packet routing to embedded projects typically employing packet radios like LoRa.
+
+It is commercially known as the 'R2' protocol, and is the successor LoRa routing engine to the ['Ripple' project](https://buymeacoffee.com/ripplebiz).
+
+At present it is mostly aimed at Arduino projects, using the [PlatformIO](https://docs.platformio.org) tools, but could potentially be integrated into other environments.
+
+## Getting Started
+
+You'll need to install PlatformIO, and an IDE in which it runs, like VSCode. Once installed, you should just be able to open this folder as a project, and it will read the platformio.ini file, and bring in all the required dependencies.
+
+There are a number of build environments defined in the platformio.ini file, all targeting the Heltec V3 LoRa boards. For example, **[env:Heltec_v3_chat_alice]** is the target for building/running the 'secure chat' sample app as the user 'Alice'. There is a similar env, configured to run the secure chat as the user 'Bob'.
+
+Try running these two examples first, flashing to two separate Heltec V3's, and use the Serial Monitor to interact with the *very basic* command-line interface.
+
+## Other Example Apps
+
+There is also a pair of examples, **'ping_client'** and **'ping_server'** which has some very basic constructs for setting up a node in a 'server'-like role, and another as client.
+
+There is also a **'simple_repeater'** example, which should function as a basic repeater to ALL of the various samples, like the chat ones. It also defines a few examples of some 'remote admin', like setting the clock. The **'test_admin'** example is an example of an app that remotely monitors and sends commands to the 'simple_repeater' nodes.
+
+## To-Do's
+
+Will hopefully figure out how to make this a registered PlatformIO library, so it can just be added in **lib_deps** in your own project.
+
+## Acknowledgments
+
+This project is insipired from/by the [Reticulum project, by Mark Qvist](https://reticulum.network/start.html). I recommend having a look at RNS (Reticulum Network Stack) and study, almost as a pre-requisite to this project.
+

examples/ping_client/main.cpp

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+#include <Arduino.h>   // needed for PlatformIO
+#include <Mesh.h>
+#include <SPIFFS.h>
+
+#define RADIOLIB_STATIC_ONLY 1
+#include <RadioLib.h>
+#include <helpers/RadioLibWrappers.h>
+#include <helpers/ArduinoHelpers.h>
+#include <helpers/StaticPoolPacketManager.h>
+#include <helpers/SimpleSeenTable.h>
+
+/* ------------------------------ Config -------------------------------- */
+
+#ifdef HELTEC_LORA_V3
+  #include <helpers/HeltecV3Board.h>
+  static HeltecV3Board board;
+#else
+  #error "need to provide a 'board' object"
+#endif
+
+/* ------------------------------ Code -------------------------------- */
+
+class MyMesh : public mesh::Mesh {
+  SimpleSeenTable* _table;
+  uint32_t last_advert_timestamp = 0;
+  mesh::Identity server_id;
+  uint8_t server_secret[PUB_KEY_SIZE];
+  int server_path_len = -1;
+  uint8_t server_path[MAX_PATH_SIZE];
+  bool got_adv = false;
+
+protected:
+  int searchPeersByHash(const uint8_t* hash) override {
+    if (got_adv && server_id.isHashMatch(hash)) {
+      return 1;
+    }
+    return 0;  // not found
+  }
+
+  void onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len) override {
+    if (memcmp(app_data, "PING", 4) == 0) {
+      Serial.println("Received advertisement from a PING server");
+
+      // check for replay attacks
+      if (timestamp > last_advert_timestamp) {
+        last_advert_timestamp = timestamp;
+
+        server_id = id;
+        self_id.calcSharedSecret(server_secret, id);  // calc ECDH shared secret
+        got_adv = true;
+      }
+    }
+  }
+
+  void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, uint8_t* data, size_t len) override {
+    if (type == PAYLOAD_TYPE_RESPONSE) {
+      if (_table->hasSeenPacket(packet)) return;
+
+      Serial.println("Received PING Reply!");
+
+      if (packet->isRouteFlood()) {
+        // let server know path TO here, so they can use sendDirect() for future ping responses
+        mesh::Packet* path = createPathReturn(server_id, server_secret, packet->path, packet->path_len, 0, NULL, 0);
+        if (path) sendFlood(path);
+      }
+    }
+  }
+
+  void onPeerPathRecv(mesh::Packet* packet, int sender_idx, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override {
+    if (_table->hasSeenPacket(packet)) return;
+
+    // must be from server_id 
+    Serial.printf("PATH to server, path_len=%d\n", (uint32_t) path_len);
+
+    memcpy(server_path, path, server_path_len = path_len);  // store a copy of path, for sendDirect()
+
+    if (packet->isRouteFlood()) {
+      // send a reciprocal return path to sender, but send DIRECTLY!
+      mesh::Packet* rpath = createPathReturn(server_id, server_secret, packet->path, packet->path_len, 0, NULL, 0);
+      if (rpath) sendDirect(rpath, path, path_len);
+    }
+
+    if (extra_type == PAYLOAD_TYPE_RESPONSE) {
+      Serial.println("Received PING Reply!");
+    }
+  }
+
+public:
+  MyMesh(mesh::Radio& radio, mesh::RNG& rng, mesh::RTCClock& rtc, SimpleSeenTable& table)
+     : mesh::Mesh(radio, *new ArduinoMillis(), rng, rtc, *new StaticPoolPacketManager(16)), _table(&table)
+  {
+  }
+
+  void sendPingPacket() {
+    if (!got_adv) return;   // have not received Advert yet
+
+    uint32_t now = getRTCClock()->getCurrentTime(); // important, need timestamp in packet, so that packet_hash will be unique
+    mesh::Packet* ping = createDatagram(PAYLOAD_TYPE_ANON_REQ, server_id, server_secret, (uint8_t *) &now, sizeof(now));
+
+    if (ping) {
+      if (server_path_len < 0) {
+        sendFlood(ping);
+      } else {
+        sendDirect(ping, server_path, server_path_len);
+      }
+    }
+  }
+
+};
+
+SPIClass spi;
+StdRNG fast_rng;
+SimpleSeenTable table;
+SX1262 radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi);
+MyMesh the_mesh(*new RadioLibWrapper(radio, board), fast_rng, *new VolatileRTCClock(), table);
+unsigned long nextPing;
+
+void halt() {
+  while (1) ;
+}
+
+void setup() {
+  Serial.begin(115200);
+
+  board.begin();
+  spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI);
+  int status = radio.begin(915.0, 250, 9, 5, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, 22);
+  if (status != RADIOLIB_ERR_NONE) {
+    Serial.print("ERROR: radio init failed: ");
+    Serial.println(status);
+    halt();
+  }
+  fast_rng.begin(radio.random(0x7FFFFFFF));
+  the_mesh.begin();
+
+  RadioNoiseListener true_rng(radio);
+  the_mesh.self_id = mesh::LocalIdentity(&true_rng);  // create new random identity
+
+  nextPing = 0;
+}
+
+void loop() {
+  if (the_mesh.millisHasNowPassed(nextPing)) {
+    the_mesh.sendPingPacket();
+
+    nextPing = the_mesh.futureMillis(10000);  // attempt ping every 10 seconds
+  }
+  the_mesh.loop();
+}

examples/ping_server/main.cpp

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+#include <Arduino.h>   // needed for PlatformIO
+#include <Mesh.h>
+#include <SPIFFS.h>
+
+#define RADIOLIB_STATIC_ONLY 1
+#include <RadioLib.h>
+#include <helpers/RadioLibWrappers.h>
+#include <helpers/ArduinoHelpers.h>
+#include <helpers/StaticPoolPacketManager.h>
+
+/* ------------------------------ Config -------------------------------- */
+
+#ifdef HELTEC_LORA_V3
+  #include <helpers/HeltecV3Board.h>
+  static HeltecV3Board board;
+#else
+  #error "need to provide a 'board' object"
+#endif
+
+/* ------------------------------ Code -------------------------------- */
+
+struct ClientInfo {
+  mesh::Identity id;
+  uint32_t last_timestamp;
+  uint8_t secret[PUB_KEY_SIZE];
+  int out_path_len;
+  uint8_t out_path[MAX_PATH_SIZE];
+};
+
+#define MAX_CLIENTS   4
+
+class MyMesh : public mesh::Mesh {
+  int num_clients;
+  ClientInfo known_clients[MAX_CLIENTS];
+
+  ClientInfo* putClient(const mesh::Identity& id) {
+    for (int i = 0; i < num_clients; i++) {
+      if (id.matches(known_clients[i].id)) return &known_clients[i];  // already known
+    }
+    if (num_clients < MAX_CLIENTS) {
+      auto newClient = &known_clients[num_clients++];
+      newClient->id = id;
+      newClient->out_path_len = -1;  // initially out_path is unknown
+      newClient->last_timestamp = 0;
+      self_id.calcSharedSecret(newClient->secret, id);   // calc ECDH shared secret
+      return newClient;
+    }
+    return NULL;  // table is full
+  }
+
+protected:
+  void onAnonDataRecv(mesh::Packet* packet, uint8_t type, const mesh::Identity& sender, uint8_t* data, size_t len) override {
+    if (type == PAYLOAD_TYPE_ANON_REQ) {  // received a PING!
+      uint32_t timestamp;
+      memcpy(&timestamp, data, 4);
+
+      auto client = putClient(sender);  // add to known clients (if not already known)
+      if (client == NULL || timestamp <= client->last_timestamp) {
+        return;  // FATAL: client table is full -OR- replay attack -OR- have seen this packet before
+      }
+
+      client->last_timestamp = timestamp;
+
+      uint32_t now = getRTCClock()->getCurrentTime(); // response packets always prefixed with timestamp
+
+      if (packet->isRouteFlood()) {
+        // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the Ping response
+        mesh::Packet* path = createPathReturn(sender, client->secret, packet->path, packet->path_len,
+                                              PAYLOAD_TYPE_RESPONSE, (uint8_t *) &now, sizeof(now));
+        if (path) sendFlood(path);
+      } else {
+        mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, sender, client->secret, (uint8_t *) &now, sizeof(now));
+        if (reply) {
+          if (client->out_path_len >= 0) {  // we have an out_path, so send DIRECT
+            sendDirect(reply, client->out_path, client->out_path_len);
+          } else {
+            sendFlood(reply);
+          }
+        }
+      }
+    }
+  }
+
+  int  matching_peer_indexes[MAX_CLIENTS];
+
+  int searchPeersByHash(const uint8_t* hash) override {
+    int n = 0;
+    for (int i = 0; i < num_clients; i++) {
+      if (known_clients[i].id.isHashMatch(hash)) {
+        matching_peer_indexes[n++] = i;  // store the INDEXES of matching contacts (for subsequent 'peer' methods)
+      }
+    }
+    return n;
+  }
+
+  // not needed for this example, but for sake of 'completeness' of Mesh impl
+  void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override {
+    if (peer_idx >= 0 && peer_idx < MAX_CLIENTS) {
+      // lookup pre-calculated shared_secret
+      int i = matching_peer_indexes[peer_idx];
+      memcpy(dest_secret, known_clients[i].secret, PUB_KEY_SIZE);
+    } else {
+      MESH_DEBUG_PRINTLN("Invalid peer_idx: %d", peer_idx);
+    }
+  }
+
+  void onPeerPathRecv(mesh::Packet* packet, int sender_idx, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override {
+    if (sender_idx >= 0 && sender_idx < MAX_CLIENTS) {
+      Serial.printf("PATH to client, path_len=%d\n", (uint32_t) path_len);
+
+      // TODO: prevent replay attacks
+
+      int i = matching_peer_indexes[sender_idx];
+      if (i >= 0 && i < num_clients) {
+        auto client = &known_clients[i];  // get from our known_clients table (sender SHOULD already be known in this context)
+        memcpy(client->out_path, path, client->out_path_len = path_len);  // store a copy of path, for sendDirect()
+      }
+    } else {
+      MESH_DEBUG_PRINTLN("Invalid sender_idx: %d", sender_idx);
+    }
+
+    // NOTE: no reciprocal path send!!
+  }
+
+public:
+  MyMesh(mesh::Radio& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc)
+     : mesh::Mesh(radio, ms, rng, rtc, *new StaticPoolPacketManager(16))
+  {
+    num_clients = 0;
+  }
+};
+
+SPIClass spi;
+StdRNG fast_rng;
+SX1262 radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi);
+MyMesh the_mesh(*new RadioLibWrapper(radio, board), *new ArduinoMillis(), fast_rng, *new VolatileRTCClock());
+
+unsigned long nextAnnounce;
+
+void halt() {
+  while (1) ;
+}
+
+void setup() {
+  Serial.begin(115200);
+
+  board.begin();
+  spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI);
+  int status = radio.begin(915.0, 250, 9, 5, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, 22);
+  if (status != RADIOLIB_ERR_NONE) {
+    Serial.print("ERROR: radio init failed: ");
+    Serial.println(status);
+    halt();
+  }
+  fast_rng.begin(radio.random(0x7FFFFFFF));
+  the_mesh.begin();
+
+  RadioNoiseListener true_rng(radio);
+  the_mesh.self_id = mesh::LocalIdentity(&true_rng);  // create new random identity
+
+  nextAnnounce = 0;
+}
+
+void loop() {
+  if (the_mesh.millisHasNowPassed(nextAnnounce)) {
+    mesh::Packet* pkt = the_mesh.createAdvert(the_mesh.self_id, (const uint8_t *)"PING", 4);
+    if (pkt) the_mesh.sendFlood(pkt);
+
+    nextAnnounce = the_mesh.futureMillis(30000);  // announce every 30 seconds (test only, don't do in production!)
+  }
+  the_mesh.loop();
+
+  // TODO: periodically check for OLD entries in known_clients[], and evict
+}

examples/simple_repeater/main.cpp

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+#include <Arduino.h>   // needed for PlatformIO
+#include <Mesh.h>
+#include <SPIFFS.h>
+
+#define RADIOLIB_STATIC_ONLY 1
+#include <RadioLib.h>
+#include <helpers/CustomSX1262Wrapper.h>
+#include <helpers/ArduinoHelpers.h>
+#include <helpers/StaticPoolPacketManager.h>
+#include <helpers/SimpleMeshTables.h>
+#include <helpers/IdentityStore.h>
+
+/* ------------------------------ Config -------------------------------- */
+
+#define  ANNOUNCE_DATA   "repeater:v1"
+
+#define  ADMIN_PASSWORD  "h^(kl@#)"
+
+#if defined(HELTEC_LORA_V3)
+  #include <helpers/HeltecV3Board.h>
+  static HeltecV3Board board;
+#else
+  #error "need to provide a 'board' object"
+#endif
+
+/* ------------------------------ Code -------------------------------- */
+
+#define CMD_GET_STATS      0x01
+#define CMD_SET_CLOCK      0x02
+#define CMD_SEND_ANNOUNCE  0x03
+#define CMD_SET_CONFIG     0x04
+
+struct RepeaterStats {
+  uint16_t batt_milli_volts;
+  uint16_t curr_tx_queue_len;
+  uint16_t curr_free_queue_len;
+  int16_t  last_rssi;
+  uint32_t n_packets_recv;
+  uint32_t n_packets_sent;
+  uint32_t total_air_time_secs;
+  uint32_t total_up_time_secs;
+};
+
+struct ClientInfo {
+  mesh::Identity id;
+  uint32_t last_timestamp;
+  uint8_t secret[PUB_KEY_SIZE];
+  int out_path_len;
+  uint8_t out_path[MAX_PATH_SIZE];
+};
+
+#define MAX_CLIENTS   4
+
+class MyMesh : public mesh::Mesh {
+  RadioLibWrapper* my_radio;
+  mesh::MeshTables* _tables;
+  float airtime_factor;
+  uint8_t reply_data[MAX_PACKET_PAYLOAD];
+  int num_clients;
+  ClientInfo known_clients[MAX_CLIENTS];
+
+  ClientInfo* putClient(const mesh::Identity& id) {
+    for (int i = 0; i < num_clients; i++) {
+      if (id.matches(known_clients[i].id)) return &known_clients[i];  // already known
+    }
+    if (num_clients < MAX_CLIENTS) {
+      auto newClient = &known_clients[num_clients++];
+      newClient->id = id;
+      newClient->out_path_len = -1;  // initially out_path is unknown
+      newClient->last_timestamp = 0;
+      self_id.calcSharedSecret(newClient->secret, id);   // calc ECDH shared secret
+      return newClient;
+    }
+    return NULL;  // table is full
+  }
+
+  int handleRequest(ClientInfo* sender, uint8_t* payload, size_t payload_len) { 
+    uint32_t now = getRTCClock()->getCurrentTime();
+    memcpy(reply_data, &now, 4);   // response packets always prefixed with timestamp
+
+    switch (payload[0]) {
+      case CMD_GET_STATS: {
+        uint32_t max_age_secs;
+        if (payload_len >= 5) {
+          memcpy(&max_age_secs, &payload[1], 4);    // first param in request pkt
+        } else {
+          max_age_secs = 12*60*60;   // default, 12 hours
+        }
+
+        RepeaterStats stats;
+        stats.batt_milli_volts = board.getBattMilliVolts();
+        stats.curr_tx_queue_len = _mgr->getOutboundCount();
+        stats.curr_free_queue_len = _mgr->getFreeCount();
+        stats.last_rssi = (int16_t) my_radio->getLastRSSI();
+        stats.n_packets_recv = my_radio->getPacketsRecv();
+        stats.n_packets_sent = my_radio->getPacketsSent();
+        stats.total_air_time_secs = getTotalAirTime() / 1000;
+        stats.total_up_time_secs = _ms->getMillis() / 1000;
+
+        memcpy(&reply_data[4], &stats, sizeof(stats));
+
+        return 4 + sizeof(stats);  //  reply_len
+      }
+      case CMD_SET_CLOCK: {
+        if (payload_len >= 5) {
+          uint32_t curr_epoch_secs;
+          memcpy(&curr_epoch_secs, &payload[1], 4);    // first param is current UNIX time
+
+          if (curr_epoch_secs > now) {   // time can only go forward!!
+            getRTCClock()->setCurrentTime(curr_epoch_secs);
+            memcpy(&reply_data[4], "OK", 2);
+          } else {
+            memcpy(&reply_data[4], "ER", 2);
+          }
+          return 4 + 2;   //  reply_len
+        }
+        return 0;  // invalid request 
+      }
+      case CMD_SEND_ANNOUNCE: {
+        // broadcast another self Advertisement
+        auto adv = createAdvert(self_id, (const uint8_t *)ANNOUNCE_DATA, strlen(ANNOUNCE_DATA));
+        if (adv) sendFlood(adv, 1500);   // send after slight delay
+
+        memcpy(&reply_data[4], "OK", 2);
+        return 4 + 2;  // reply_len
+      }
+      case CMD_SET_CONFIG: {
+        if (payload_len >= 4 && payload_len < 32 && memcmp(&payload[1], "AF", 2) == 0) {
+          payload[payload_len] = 0;  // make it a C string
+          airtime_factor = atof((char *) &payload[3]);
+
+          memcpy(&reply_data[4], "OK", 2);
+          return 4 + 2;  // reply_len
+        }        
+        return 0;  // unknown config var
+      }
+    }
+    // unknown command
+    return 0;  // reply_len
+  }
+
+protected:
+  float getAirtimeBudgetFactor() const override {
+    return airtime_factor;
+  }
+
+  bool allowPacketForward(mesh::Packet* packet) override {
+    uint8_t hash[MAX_HASH_SIZE];
+    packet->calculatePacketHash(hash);
+
+    if (_tables->hasForwarded(hash)) return false;  // has already been forwarded
+
+    _tables->setHasForwarded(hash);  // mark packet as forwarded
+    return true;   // Yes, allow packet to be forwarded
+  }
+
+  void onAnonDataRecv(mesh::Packet* packet, uint8_t type, const mesh::Identity& sender, uint8_t* data, size_t len) override {
+    if (type == PAYLOAD_TYPE_ANON_REQ) {  // received an initial request by a possible admin client (unknown at this stage)
+      uint32_t timestamp;
+      memcpy(&timestamp, data, 4);
+
+      if (memcmp(&data[4], ADMIN_PASSWORD, 8) == 0) {  // check for valid password
+        auto client = putClient(sender);  // add to known clients (if not already known)
+        if (client == NULL || timestamp <= client->last_timestamp) {
+          return;  // FATAL: client table is full -OR- replay attack -OR- have seen this packet before
+        }
+
+        client->last_timestamp = timestamp;
+
+        uint32_t now = getRTCClock()->getCurrentTime();
+        memcpy(reply_data, &now, 4);   // response packets always prefixed with timestamp
+        memcpy(&reply_data[4], "OK", 2);
+
+        if (packet->isRouteFlood()) {
+          // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
+          mesh::Packet* path = createPathReturn(sender, client->secret, packet->path, packet->path_len,
+                                                PAYLOAD_TYPE_RESPONSE, reply_data, 4 + 2);
+          if (path) sendFlood(path);
+        } else {
+          mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, sender, client->secret, reply_data, 4 + 2);
+          if (reply) {
+            if (client->out_path_len >= 0) {  // we have an out_path, so send DIRECT
+              sendDirect(reply, client->out_path, client->out_path_len);
+            } else {
+              sendFlood(reply);
+            }
+          }
+        }
+      }
+    }
+  }
+
+  int  matching_peer_indexes[MAX_CLIENTS];
+
+  int searchPeersByHash(const uint8_t* hash) override {
+    int n = 0;
+    for (int i = 0; i < num_clients; i++) {
+      if (known_clients[i].id.isHashMatch(hash)) {
+        matching_peer_indexes[n++] = i;  // store the INDEXES of matching contacts (for subsequent 'peer' methods)
+      }
+    }
+    return n;
+  }
+
+  void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override {
+    int i = matching_peer_indexes[peer_idx];
+    if (i >= 0 && i < num_clients) {
+      // lookup pre-calculated shared_secret
+      memcpy(dest_secret, known_clients[i].secret, PUB_KEY_SIZE);
+    } else {
+      MESH_DEBUG_PRINTLN("getPeerSharedSecret: Invalid peer idx: %d", i);
+    }
+  }
+
+  void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, uint8_t* data, size_t len) override {
+     if (type == PAYLOAD_TYPE_REQ) {  // request (from a Known admin client!)
+      int i = matching_peer_indexes[sender_idx];
+
+      if (i >= 0 && i < num_clients) {  // get from our known_clients table (sender SHOULD already be known in this context)
+        auto client = &known_clients[i];
+
+        uint32_t timestamp;
+        memcpy(&timestamp, data, 4);
+
+        if (timestamp > client->last_timestamp) {  // prevent replay attacks AND receiving via multiple paths
+          int reply_len = handleRequest(client, &data[4], len - 4);
+          if (reply_len == 0) return;  // invalid command
+
+          client->last_timestamp = timestamp;
+
+          if (packet->isRouteFlood()) {
+            // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
+            mesh::Packet* path = createPathReturn(client->id, client->secret, packet->path, packet->path_len,
+                                                  PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
+            if (path) sendFlood(path);
+          } else {
+            mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, client->id, client->secret, reply_data, reply_len);
+            if (reply) {
+              if (client->out_path_len >= 0) {  // we have an out_path, so send DIRECT
+                sendDirect(reply, client->out_path, client->out_path_len);
+              } else {
+                sendFlood(reply);
+              }
+            }
+          }
+        }
+      } else {
+        MESH_DEBUG_PRINTLN("onPeerDataRecv: invalid peer idx: %d", i);
+      }
+    }
+  }
+
+  void onPeerPathRecv(mesh::Packet* packet, int sender_idx, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override {
+    // TODO: prevent replay attacks
+    int i = matching_peer_indexes[sender_idx];
+
+    if (i >= 0 && i < num_clients) {  // get from our known_clients table (sender SHOULD already be known in this context)
+      Serial.printf("PATH to client, path_len=%d\n", (uint32_t) path_len);
+      auto client = &known_clients[i];
+      memcpy(client->out_path, path, client->out_path_len = path_len);  // store a copy of path, for sendDirect()
+    } else {
+      MESH_DEBUG_PRINTLN("onPeerPathRecv: invalid peer idx: %d", i);
+    }
+
+    // NOTE: no reciprocal path send!!
+  }
+
+public:
+  MyMesh(RadioLibWrapper& radio, mesh::MillisecondClock& ms, mesh::RNG& rng, mesh::RTCClock& rtc, mesh::MeshTables& tables)
+     : mesh::Mesh(radio, ms, rng, rtc, *new StaticPoolPacketManager(32)), _tables(&tables)
+  {
+    my_radio = &radio;
+    airtime_factor = 5.0;   // 1/6th
+    num_clients = 0;
+  }
+
+  void sendSelfAdvertisement() {
+    mesh::Packet* pkt = createAdvert(self_id, (const uint8_t *)ANNOUNCE_DATA, strlen(ANNOUNCE_DATA));
+    if (pkt) {
+      sendFlood(pkt);
+    } else {
+      MESH_DEBUG_PRINTLN("ERROR: unable to create advertisement packet!");
+    }
+  }
+};
+
+#if defined(P_LORA_SCLK)
+SPIClass spi;
+CustomSX1262 radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi);
+#else
+CustomSX1262 radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY);
+#endif
+StdRNG fast_rng;
+SimpleMeshTables tables;
+MyMesh the_mesh(*new CustomSX1262Wrapper(radio, board), *new ArduinoMillis(), fast_rng, *new VolatileRTCClock(), tables);
+
+void halt() {
+  while (1) ;
+}
+
+void setup() {
+  Serial.begin(115200);
+  delay(5000);
+
+  board.begin();
+#if defined(P_LORA_SCLK)
+  spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI);
+  int status = radio.begin(915.0, 250, 9, 5, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, 22);
+#else
+  int status = radio.begin(915.0, 250, 9, 5, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, 22);
+#endif
+  if (status != RADIOLIB_ERR_NONE) {
+    Serial.print("ERROR: radio init failed: ");
+    Serial.println(status);
+    halt();
+  }
+
+  SPIFFS.begin(true);
+  IdentityStore store(SPIFFS, "/identity");
+  if (!store.load("_main", the_mesh.self_id)) {
+    the_mesh.self_id = mesh::LocalIdentity(the_mesh.getRNG());  // create new random identity
+    store.save("_main", the_mesh.self_id);
+  }
+
+  Serial.print("Repeater ID: ");
+  mesh::Utils::printHex(Serial, the_mesh.self_id.pub_key, PUB_KEY_SIZE); Serial.println();
+
+  the_mesh.begin();
+
+  // send out initial Advertisement to the mesh
+  the_mesh.sendSelfAdvertisement();
+}
+
+void loop() {
+  the_mesh.loop();
+
+  // TODO: periodically check for OLD/inactive entries in known_clients[], and evict
+}

examples/simple_secure_chat/main.cpp

@@ -0,0 +1,334 @@
+#include <Arduino.h>   // needed for PlatformIO
+#include <Mesh.h>
+#include <SPIFFS.h>
+
+#define RADIOLIB_STATIC_ONLY 1
+#include <RadioLib.h>
+#include <helpers/RadioLibWrappers.h>
+#include <helpers/ArduinoHelpers.h>
+#include <helpers/StaticPoolPacketManager.h>
+#include <helpers/SimpleSeenTable.h>
+
+/* ---------------------------------- CONFIGURATION ------------------------------------- */
+
+//#define RUN_AS_ALICE    true
+
+#if RUN_AS_ALICE
+  const char* alice_private = "B8830658388B2DDF22C3A508F4386975970CDE1E2A2A495C8F3B5727957A97629255A1392F8BA4C26A023A0DAB78BFC64D261C8E51507496DD39AFE3707E7B42";
+#else
+  const char *bob_private = "30BAA23CCB825D8020A59C936D0AB7773B07356020360FC77192813640BAD375E43BBF9A9A7537E4B9614610F1F2EF874AAB390BA9B0C2F01006B01FDDFEFF0C";
+#endif
+  const char *alice_public = "106A5136EC0DD797650AD204C065CF9B66095F6ED772B0822187785D65E11B1F";
+  const char *bob_public = "020BCEDAC07D709BD8507EC316EB5A7FF2F0939AF5057353DCE7E4436A1B9681";
+
+#ifdef HELTEC_LORA_V3
+  #include <helpers/HeltecV3Board.h>
+  static HeltecV3Board board;
+#else
+  #error "need to provide a 'board' object"
+#endif
+
+#define FLOOD_SEND_TIMEOUT_MILLIS   4000
+#define DIRECT_SEND_TIMEOUT_MILLIS  2000
+
+/* -------------------------------------------------------------------------------------- */
+
+static unsigned long txt_send_timeout;
+
+#define MAX_CONTACTS         1
+#define MAX_SEARCH_RESULTS   1
+
+#define MAX_TEXT_LEN    (10*CIPHER_BLOCK_SIZE)  // must be LESS than (MAX_PACKET_PAYLOAD - 4 - CIPHER_MAC_SIZE - 1)
+
+struct ContactInfo {
+  mesh::Identity id;
+  const char* name;
+  int out_path_len;
+  uint8_t out_path[MAX_PATH_SIZE];
+  uint32_t last_advert_timestamp;
+  uint8_t shared_secret[PUB_KEY_SIZE];
+};
+
+class MyMesh : public mesh::Mesh {
+public:
+  SimpleSeenTable* _table;
+  mesh::LocalIdentity self_id;
+  ContactInfo contacts[MAX_CONTACTS];
+  int num_contacts;
+
+  void addContact(const char* name, const mesh::Identity& id) {
+    if (num_contacts < MAX_CONTACTS) {
+      contacts[num_contacts].id = id;
+      contacts[num_contacts].name = name;
+      contacts[num_contacts].last_advert_timestamp = 0;
+      contacts[num_contacts].out_path_len = -1;
+      // only need to calculate the shared_secret once, for better performance
+      self_id.calcSharedSecret(contacts[num_contacts].shared_secret, id);
+      num_contacts++;
+    }
+  }
+
+protected:
+  int  matching_peer_indexes[MAX_SEARCH_RESULTS];
+
+  int searchPeersByHash(const uint8_t* hash) override {
+    int n = 0;
+    for (int i = 0; i < num_contacts && n < MAX_SEARCH_RESULTS; i++) {
+      if (contacts[i].id.isHashMatch(hash)) {
+        matching_peer_indexes[n++] = i;  // store the INDEXES of matching contacts (for subsequent 'peer' methods)
+      }
+    }
+    return n;
+  }
+
+  void onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len) override {
+    Serial.print("Valid Advertisement -> ");
+    mesh::Utils::printHex(Serial, id.pub_key, PUB_KEY_SIZE);
+    Serial.println();
+
+    for (int i = 0; i < num_contacts; i++) {
+      ContactInfo& from = contacts[i];
+      // check for replay attacks 
+      if (id.matches(from.id) && timestamp > from.last_advert_timestamp) {  // is from one of our contacts
+        from.last_advert_timestamp = timestamp;
+        Serial.printf("   From contact: %s\n", from.name);
+      }
+    }
+  }
+
+  void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override {
+    int i = matching_peer_indexes[peer_idx];
+    if (i >= 0 && i < num_contacts) {
+      // lookup pre-calculated shared_secret
+      memcpy(dest_secret, contacts[i].shared_secret, PUB_KEY_SIZE);
+    } else {
+      MESH_DEBUG_PRINTLN("getPeerSHharedSecret: Invalid peer idx: %d", i);
+    }
+  }
+
+  void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, uint8_t* data, size_t len) override {
+    if (type == PAYLOAD_TYPE_TXT_MSG) {
+      if (_table->hasSeenPacket(packet)) return;
+
+      int i = matching_peer_indexes[sender_idx];
+      if (i < 0 && i >= num_contacts) {
+        MESH_DEBUG_PRINTLN("onPeerDataRecv: Invalid sender idx: %d", i);
+        return;
+      }
+
+      ContactInfo& from = contacts[i];
+
+      uint32_t timestamp;
+      memcpy(&timestamp, data, 4);  // timestamp (by sender's RTC clock - which could be wrong)
+
+      // len can be > original length, but 'text' will be padded with zeroes
+      data[len] = 0; // need to make a C string again, with null terminator
+
+      Serial.print("MSG -> from ");
+      Serial.print(from.name);
+      Serial.print(": ");
+      Serial.println((const char *) &data[4]);
+
+      uint32_t ack_hash;    // calc truncated hash of the message timestamp + text + sender pub_key, to prove to sender that we got it
+      mesh::Utils::sha256((uint8_t *) &ack_hash, 4, data, len, from.id.pub_key, PUB_KEY_SIZE);
+
+      if (packet->isRouteFlood()) {
+        // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the ACK
+        mesh::Packet* path = createPathReturn(from.id, from.shared_secret, packet->path, packet->path_len,
+                                              PAYLOAD_TYPE_ACK, (uint8_t *) &ack_hash, 4);
+        if (path) sendFlood(path);
+      } else {
+        mesh::Packet* ack = createAck(ack_hash);
+        if (ack) {
+          if (from.out_path_len < 0) {
+            sendFlood(ack);
+          } else {
+            sendDirect(ack, from.out_path, from.out_path_len);
+          }
+        }
+      }
+    }
+  }
+
+  void onPeerPathRecv(mesh::Packet* packet, int sender_idx, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override {
+    if (_table->hasSeenPacket(packet)) return;
+
+    int i = matching_peer_indexes[sender_idx];
+    if (i < 0 && i >= num_contacts) {
+      MESH_DEBUG_PRINTLN("onPeerPathRecv: Invalid sender idx: %d", i);
+      return;
+    }
+
+    ContactInfo& from = contacts[i];
+    Serial.printf("PATH to: %s, path_len=%d\n", from.name, (uint32_t) path_len);
+
+    memcpy(from.out_path, path, from.out_path_len = path_len);  // store a copy of path, for sendDirect()
+
+    if (packet->isRouteFlood()) {
+      // send a reciprocal return path to sender, but send DIRECTLY!
+      mesh::Packet* rpath = createPathReturn(from.id, from.shared_secret, packet->path, packet->path_len, 0, NULL, 0);
+      if (rpath) sendDirect(rpath, path, path_len);
+    }
+
+    if (extra_type == PAYLOAD_TYPE_ACK && extra_len >= 4) {
+      // also got an encoded ACK!
+      processAck(extra);
+    }
+  }
+
+  void onAckRecv(mesh::Packet* packet, uint32_t ack_crc) override {
+    processAck((uint8_t *)&ack_crc);
+  }
+
+  void processAck(const uint8_t *data) {
+    if (memcmp(data, &expected_ack_crc, 4) == 0) {     // got an ACK from recipient
+      Serial.println("Got ACK!");
+      // NOTE: the same ACK can be received multiple times!
+      expected_ack_crc = 0;  // reset our expected hash, now that we have received ACK
+      txt_send_timeout = 0;
+    }
+  }
+
+public:
+  uint32_t expected_ack_crc;
+
+  MyMesh(mesh::Radio& radio, mesh::RNG& rng, mesh::RTCClock& rtc, SimpleSeenTable& table)
+     : mesh::Mesh(radio, *new ArduinoMillis(), rng, rtc, *new StaticPoolPacketManager(16)), _table(&table)
+  {
+    num_contacts = 0;
+  }
+
+  mesh::Packet* composeMsgPacket(ContactInfo& recipient, const char *text) {
+    int text_len = strlen(text);
+    if (text_len > MAX_TEXT_LEN) return NULL;
+
+    uint8_t temp[4+MAX_TEXT_LEN+1];
+    uint32_t timestamp = getRTCClock()->getCurrentTime();
+    memcpy(temp, &timestamp, 4);   // mostly an extra blob to help make packet_hash unique
+    memcpy(&temp[4], text, text_len);
+
+    // calc expected ACK reply
+    mesh::Utils::sha256((uint8_t *)&expected_ack_crc, 4, (const uint8_t *) temp, 4 + text_len, self_id.pub_key, PUB_KEY_SIZE);
+
+    return createDatagram(PAYLOAD_TYPE_TXT_MSG, recipient.id, recipient.shared_secret, temp, 4 + text_len);
+  }
+
+  void sendSelfAnnounce() {
+    mesh::Packet* announce = createAdvert(self_id);
+    if (announce) {
+      sendFlood(announce);
+      Serial.println("   (advert sent).");
+    } else {
+      Serial.println("   ERROR: unable to create packet.");
+    }
+  }
+};
+
+SPIClass spi;
+StdRNG fast_rng;
+SimpleSeenTable table;
+SX1262 radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi);
+MyMesh the_mesh(*new RadioLibWrapper(radio, board), fast_rng, *new VolatileRTCClock(), table);
+
+void halt() {
+  while (1) ;
+}
+
+static char command[MAX_TEXT_LEN+1];
+
+void setup() {
+  Serial.begin(115200);
+
+  board.begin();
+  spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI);
+  int status = radio.begin(915.0, 250, 9, 5, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, 22);
+  if (status != RADIOLIB_ERR_NONE) {
+    Serial.print("ERROR: radio init failed: ");
+    Serial.println(status);
+    halt();
+  }
+
+  fast_rng.begin(radio.random(0x7FFFFFFF));
+
+#if RUN_AS_ALICE
+  Serial.println("   --- user: Alice ---");
+  the_mesh.self_id = mesh::LocalIdentity(alice_private, alice_public);
+  the_mesh.addContact("Bob", mesh::Identity(bob_public));
+#else
+  Serial.println("   --- user: Bob ---");
+  the_mesh.self_id = mesh::LocalIdentity(bob_private, bob_public);
+  the_mesh.addContact("Alice", mesh::Identity(alice_public));
+#endif
+  Serial.println("Help:");
+  Serial.println("  enter 'ann' to announce presence to mesh");
+  Serial.println("  enter 'send {message text}' to send a message");
+
+  the_mesh.begin();
+
+  command[0] = 0;
+  txt_send_timeout = 0;
+
+  // send out initial Announce to the mesh
+  the_mesh.sendSelfAnnounce();
+}
+
+void loop() {
+  int len = strlen(command);
+  while (Serial.available() && len < sizeof(command)-1) {
+    char c = Serial.read();
+    if (c != '\n') { 
+      command[len++] = c;
+      command[len] = 0;
+    }
+    Serial.print(c);
+  }
+  if (len == sizeof(command)-1) {  // command buffer full
+    command[sizeof(command)-1] = '\r';
+  }
+
+  if (len > 0 && command[len - 1] == '\r') {  // received complete line
+    command[len - 1] = 0;  // replace newline with C string null terminator
+
+    if (memcmp(command, "send ", 5) == 0) {
+      // TODO: some way to select recipient??
+      ContactInfo& recipient = the_mesh.contacts[0];  // just send to first contact for now
+
+      const char *text = &command[5];
+      mesh::Packet* pkt = the_mesh.composeMsgPacket(recipient, text);
+      if (pkt) {
+        if (recipient.out_path_len < 0) {
+          the_mesh.sendFlood(pkt);
+          txt_send_timeout = the_mesh.futureMillis(FLOOD_SEND_TIMEOUT_MILLIS);
+        } else {
+          the_mesh.sendDirect(pkt, recipient.out_path, recipient.out_path_len);
+          txt_send_timeout = the_mesh.futureMillis(DIRECT_SEND_TIMEOUT_MILLIS);
+        }
+        Serial.println("   (message sent)");
+      } else {
+        Serial.println("   ERROR: unable to create packet.");
+      }
+    } else if (strcmp(command, "ann") == 0) {
+      the_mesh.sendSelfAnnounce();
+    } else if (strcmp(command, "key") == 0) {
+      mesh::LocalIdentity new_id(the_mesh.getRNG());
+      new_id.printTo(Serial);
+    } else {
+      Serial.print("   ERROR: unknown command: "); Serial.println(command);
+    }
+
+    command[0] = 0;  // reset command buffer
+  }
+
+  if (txt_send_timeout && the_mesh.millisHasNowPassed(txt_send_timeout)) {
+    // failed to get an ACK
+    ContactInfo& recipient = the_mesh.contacts[0];  // just the one contact for now
+    Serial.println("   ERROR: timed out, no ACK.");
+
+    // path to our contact is now possibly broken, fallback to Flood mode
+    recipient.out_path_len = -1;
+
+    txt_send_timeout = 0;
+  }
+
+  the_mesh.loop();
+}

examples/test_admin/main.cpp

@@ -0,0 +1,304 @@
+#include <Arduino.h>   // needed for PlatformIO
+#include <Mesh.h>
+#include <SPIFFS.h>
+
+#define RADIOLIB_STATIC_ONLY 1
+#include <RadioLib.h>
+#include <helpers/CustomSX1262Wrapper.h>
+#include <helpers/ArduinoHelpers.h>
+#include <helpers/SimpleSeenTable.h>
+#include <helpers/StaticPoolPacketManager.h>
+
+/* ---------------------------------- CONFIGURATION ------------------------------------- */
+
+#define  ADMIN_PASSWORD  "h^(kl@#)"
+
+#ifdef HELTEC_LORA_V3
+  #include <helpers/HeltecV3Board.h>
+  static HeltecV3Board board;
+#else
+  #error "need to provide a 'board' object"
+#endif
+
+/* -------------------------------------------------------------------------------------- */
+
+#define MAX_TEXT_LEN    (10*CIPHER_BLOCK_SIZE)  // must be LESS than (MAX_PACKET_PAYLOAD - FROM_HASH_LEN - CIPHER_MAC_SIZE - 1)
+
+#define CMD_GET_STATS      0x01
+#define CMD_SET_CLOCK      0x02
+#define CMD_SEND_ANNOUNCE  0x03
+#define CMD_SET_CONFIG     0x04
+
+struct RepeaterStats {
+  uint16_t batt_milli_volts;
+  uint16_t curr_tx_queue_len;
+  uint16_t curr_free_queue_len;
+  int16_t  last_rssi;
+  uint32_t n_packets_recv;
+  uint32_t n_packets_sent;
+  uint32_t total_air_time_secs;
+  uint32_t total_up_time_secs;
+};
+
+class MyMesh : public mesh::Mesh {
+  SimpleSeenTable* _table;
+  uint32_t last_advert_timestamp = 0;
+  mesh::Identity server_id;
+  uint8_t server_secret[PUB_KEY_SIZE];
+  int server_path_len = -1;
+  uint8_t server_path[MAX_PATH_SIZE];
+  bool got_adv = false;
+
+protected:
+  int searchPeersByHash(const uint8_t* hash) override {
+    if (got_adv && server_id.isHashMatch(hash)) {
+      return 1;
+    }
+    return 0;  // not found
+  }
+
+  void onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len) override {
+    if (memcmp(app_data, "repeater:", 9) == 0) {
+      Serial.println("Received advertisement from a repeater!");
+
+      // check for replay attacks
+      if (timestamp > last_advert_timestamp) {
+        last_advert_timestamp = timestamp;
+
+        server_id = id;
+        self_id.calcSharedSecret(server_secret, id);  // calc ECDH shared secret
+        got_adv = true;
+
+        // 'login' to repeater. (mainly lets it know our public key)
+        uint32_t now = getRTCClock()->getCurrentTime(); // important, need timestamp in packet, so that packet_hash will be unique
+        uint8_t temp[4 + 8];
+        memcpy(temp, &now, 4);
+        memcpy(&temp[4], ADMIN_PASSWORD, 8);
+
+        mesh::Packet* login = createDatagram(PAYLOAD_TYPE_ANON_REQ, server_id, server_secret, temp, sizeof(temp));
+        if (login) sendFlood(login);  // server_path won't be known yet
+      }
+    }
+  }
+
+  void handleResponse(const uint8_t* reply, size_t reply_len) {
+    if (reply_len >= 4 + sizeof(RepeaterStats)) {      // got an GET_STATS reply from repeater
+      RepeaterStats stats;
+      memcpy(&stats, &reply[4], sizeof(stats));
+      Serial.println("Repeater Stats:");
+      Serial.printf("  battery: %d mV\n", (uint32_t) stats.batt_milli_volts);
+      Serial.printf("  tx queue: %d\n", (uint32_t) stats.curr_tx_queue_len);
+      Serial.printf("  free queue: %d\n", (uint32_t) stats.curr_free_queue_len);
+      Serial.printf("  last RSSI: %d\n", (int) stats.last_rssi);
+      Serial.printf("  num recv: %d\n", stats.n_packets_recv);
+      Serial.printf("  num sent: %d\n", stats.n_packets_sent);
+      Serial.printf("  air time (secs): %d\n", stats.total_air_time_secs);
+      Serial.printf("  up time (secs): %d\n", stats.total_up_time_secs);
+    } else if (reply_len > 4) {   // got an SET_* reply from repeater
+      char tmp[MAX_PACKET_PAYLOAD];
+      memcpy(tmp, &reply[4], reply_len - 4);
+      tmp[reply_len - 4] = 0;  // make a C string of reply
+
+      Serial.print("Reply: "); Serial.println(tmp);
+    }
+  }
+
+  void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, uint8_t* data, size_t len) override {
+    if (type == PAYLOAD_TYPE_RESPONSE) {
+      if (_table->hasSeenPacket(packet)) return;
+
+      handleResponse(data, len);
+
+      if (packet->isRouteFlood()) {
+        // let server know path TO here, so they can use sendDirect() for future ping responses
+        mesh::Packet* path = createPathReturn(server_id, server_secret, packet->path, packet->path_len, 0, NULL, 0);
+        if (path) sendFlood(path);
+      }
+    }
+  }
+
+  void onPeerPathRecv(mesh::Packet* packet, int sender_idx, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override {
+    if (_table->hasSeenPacket(packet)) return;
+
+    // must be from server_id 
+    Serial.printf("PATH to repeater, path_len=%d\n", (uint32_t) path_len);
+
+    memcpy(server_path, path, server_path_len = path_len);  // store a copy of path, for sendDirect()
+
+    if (packet->isRouteFlood()) {
+      // send a reciprocal return path to sender, but send DIRECTLY!
+      mesh::Packet* rpath = createPathReturn(server_id, server_secret, packet->path, packet->path_len, 0, NULL, 0);
+      if (rpath) sendDirect(rpath, path, path_len);
+    }
+
+    if (extra_type == PAYLOAD_TYPE_RESPONSE) {
+      handleResponse(extra, extra_len);
+    }
+  }
+
+public:
+  MyMesh(mesh::Radio& radio, mesh::RNG& rng, mesh::RTCClock& rtc, SimpleSeenTable& table)
+     : mesh::Mesh(radio, *new ArduinoMillis(), rng, rtc, *new StaticPoolPacketManager(16)), _table(&table)
+  {
+  }
+
+  mesh::Packet* createStatsRequest(uint32_t max_age) {
+    uint8_t payload[9];
+    uint32_t now = getRTCClock()->getCurrentTime();
+    memcpy(payload, &now, 4);
+    payload[4] = CMD_GET_STATS;
+    memcpy(&payload[5], &max_age, 4);
+
+    return createDatagram(PAYLOAD_TYPE_REQ, server_id, server_secret, payload, sizeof(payload));
+  }
+
+  mesh::Packet* createSetClockRequest(uint32_t timestamp) {
+    uint8_t payload[9];
+    uint32_t now = getRTCClock()->getCurrentTime();
+    memcpy(payload, &now, 4);
+    payload[4] = CMD_SET_CLOCK;
+    memcpy(&payload[5], &now, 4);  // repeated :-(
+
+    return createDatagram(PAYLOAD_TYPE_REQ, server_id, server_secret, payload, sizeof(payload));
+  }
+
+  mesh::Packet* createSetAirtimeFactorRequest(float airtime_factor) {
+    uint8_t payload[16];
+    uint32_t now = getRTCClock()->getCurrentTime();
+    memcpy(payload, &now, 4);
+    payload[4] = CMD_SET_CONFIG;
+    sprintf((char *) &payload[5], "AF%f", airtime_factor);
+
+    return createDatagram(PAYLOAD_TYPE_REQ, server_id, server_secret, payload, sizeof(payload));
+  }
+
+  mesh::Packet* createAnnounceRequest() {
+    uint8_t payload[5];
+    uint32_t now = getRTCClock()->getCurrentTime();
+    memcpy(payload, &now, 4);
+    payload[4] = CMD_SEND_ANNOUNCE;
+
+    return createDatagram(PAYLOAD_TYPE_REQ, server_id, server_secret, payload, sizeof(payload));
+  }
+
+  mesh::Packet* parseCommand(char* command) {
+    if (strcmp(command, "stats") == 0) {
+      return createStatsRequest(60*60);    // max_age = one hour
+    } else if (memcmp(command, "setclock ", 9) == 0) {
+      uint32_t timestamp = atol(&command[9]);
+      return createSetClockRequest(timestamp);
+    } else if (memcmp(command, "set AF=", 7) == 0) {
+      float factor = atof(&command[7]);
+      return createSetAirtimeFactorRequest(factor);
+    } else if (strcmp(command, "ann") == 0) {
+      return createAnnounceRequest();
+    }
+    return NULL;  // unknown command
+  }
+
+  void sendCommand(mesh::Packet* pkt) {
+    if (server_path_len < 0) {
+      sendFlood(pkt);
+    } else {
+      sendDirect(pkt, server_path, server_path_len);
+    }
+  }
+};
+
+StdRNG fast_rng;
+SimpleSeenTable table;
+#if defined(P_LORA_SCLK)
+SPIClass spi;
+CustomSX1262 radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY, spi);
+#else
+CustomSX1262 radio = new Module(P_LORA_NSS, P_LORA_DIO_1, P_LORA_RESET, P_LORA_BUSY);
+#endif
+MyMesh the_mesh(*new CustomSX1262Wrapper(radio, board), fast_rng, *new VolatileRTCClock(), table);
+
+void halt() {
+  while (1) ;
+}
+
+static char command[MAX_TEXT_LEN+1];
+
+#include <SHA256.h>
+
+void setup() {
+  Serial.begin(115200);
+  delay(5000);
+
+  board.begin();
+#if defined(P_LORA_SCLK)
+  spi.begin(P_LORA_SCLK, P_LORA_MISO, P_LORA_MOSI);
+  int status = radio.begin(915.0, 250, 9, 5, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, 22);
+#else
+  int status = radio.begin(915.0, 250, 9, 5, RADIOLIB_SX126X_SYNC_WORD_PRIVATE, 22);
+#endif
+  if (status != RADIOLIB_ERR_NONE) {
+    Serial.print("ERROR: radio init failed: ");
+    Serial.println(status);
+    halt();
+  }
+
+  fast_rng.begin(radio.random(0x7FFFFFFF));
+
+/* add this to tests
+  uint8_t mac_encrypted[CIPHER_MAC_SIZE+CIPHER_BLOCK_SIZE];
+  const char *orig_msg = "original";
+  int enc_len = mesh::Utils::encryptThenMAC(mesh.admin_secret, mac_encrypted, (const uint8_t *) orig_msg, strlen(orig_msg));
+  char decrypted[CIPHER_BLOCK_SIZE*2];
+  int len = mesh::Utils::MACThenDecrypt(mesh.admin_secret, (uint8_t *)decrypted, mac_encrypted, enc_len);
+  if (len > 0) {
+    decrypted[len] = 0;
+    Serial.print("decrypted text: "); Serial.println(decrypted);
+  } else {
+    Serial.println("MACs DONT match!");
+  }
+*/
+
+  Serial.println("Help:");
+  Serial.println("  enter 'key' to generate new keypair");
+  Serial.println("  enter 'stats' to request repeater stats");
+  Serial.println("  enter 'setclock {unix-epoch-seconds}' to set repeater's clock");
+  Serial.println("  enter 'set AF={factor}' to set airtime budget factor");
+  Serial.println("  enter 'ann' to make repeater re-announce to mesh");
+
+  the_mesh.begin();
+
+  command[0] = 0;
+}
+
+void loop() {
+  int len = strlen(command);
+  while (Serial.available() && len < sizeof(command)-1) {
+    char c = Serial.read();
+    if (c != '\n') { 
+      command[len++] = c;
+      command[len] = 0;
+    }
+    Serial.print(c);
+  }
+  if (len == sizeof(command)-1) {  // command buffer full
+    command[sizeof(command)-1] = '\r';
+  }
+
+  if (len > 0 && command[len - 1] == '\r') {  // received complete line
+    command[len - 1] = 0;  // replace newline with C string null terminator
+
+    if (strcmp(command, "key") == 0) {
+      mesh::LocalIdentity new_id(the_mesh.getRNG());
+      new_id.printTo(Serial);
+    } else {
+      mesh::Packet* pkt = the_mesh.parseCommand(command);
+      if (pkt) { 
+        the_mesh.sendCommand(pkt);
+        Serial.println("   (request sent)");
+      } else {
+        Serial.print("   ERROR: unknown command: "); Serial.println(command);
+      }
+    }
+    command[0] = 0;  // reset command buffer
+  }
+
+  the_mesh.loop();
+}

include/README

@@ -0,0 +1,39 @@
+
+This directory is intended for project header files.
+
+A header file is a file containing C declarations and macro definitions
+to be shared between several project source files. You request the use of a
+header file in your project source file (C, C++, etc) located in `src` folder
+by including it, with the C preprocessing directive `#include'.
+
+```src/main.c
+
+#include "header.h"
+
+int main (void)
+{
+ ...
+}
+```
+
+Including a header file produces the same results as copying the header file
+into each source file that needs it. Such copying would be time-consuming
+and error-prone. With a header file, the related declarations appear
+in only one place. If they need to be changed, they can be changed in one
+place, and programs that include the header file will automatically use the
+new version when next recompiled. The header file eliminates the labor of
+finding and changing all the copies as well as the risk that a failure to
+find one copy will result in inconsistencies within a program.
+
+In C, the usual convention is to give header files names that end with `.h'.
+It is most portable to use only letters, digits, dashes, and underscores in
+header file names, and at most one dot.
+
+Read more about using header files in official GCC documentation:
+
+* Include Syntax
+* Include Operation
+* Once-Only Headers
+* Computed Includes
+
+https://gcc.gnu.org/onlinedocs/cpp/Header-Files.html

lib/README

@@ -0,0 +1,46 @@
+
+This directory is intended for project specific (private) libraries.
+PlatformIO will compile them to static libraries and link into executable file.
+
+The source code of each library should be placed in a an own separate directory
+("lib/your_library_name/[here are source files]").
+
+For example, see a structure of the following two libraries `Foo` and `Bar`:
+
+|--lib
+|  |
+|  |--Bar
+|  |  |--docs
+|  |  |--examples
+|  |  |--src
+|  |     |- Bar.c
+|  |     |- Bar.h
+|  |  |- library.json (optional, custom build options, etc) https://docs.platformio.org/page/librarymanager/config.html
+|  |
+|  |--Foo
+|  |  |- Foo.c
+|  |  |- Foo.h
+|  |
+|  |- README --> THIS FILE
+|
+|- platformio.ini
+|--src
+   |- main.c
+
+and a contents of `src/main.c`:
+```
+#include <Foo.h>
+#include <Bar.h>
+
+int main (void)
+{
+  ...
+}
+
+```
+
+PlatformIO Library Dependency Finder will find automatically dependent
+libraries scanning project source files.
+
+More information about PlatformIO Library Dependency Finder
+- https://docs.platformio.org/page/librarymanager/ldf.html

lib/ed25519/add_scalar.c

@@ -0,0 +1,69 @@
+#include "ed_25519.h"
+#include "ge.h"
+#include "sc.h"
+#include "sha512.h"
+
+
+/* see http://crypto.stackexchange.com/a/6215/4697 */
+void ed25519_add_scalar(unsigned char *public_key, unsigned char *private_key, const unsigned char *scalar) {
+    const unsigned char SC_1[32] = {1}; /* scalar with value 1 */
+    
+    unsigned char n[32]; 
+    ge_p3 nB;
+    ge_p1p1 A_p1p1;
+    ge_p3 A;
+    ge_p3 public_key_unpacked;
+    ge_cached T;
+
+    sha512_context hash;
+    unsigned char hashbuf[64];
+
+    int i;
+
+    /* copy the scalar and clear highest bit */
+    for (i = 0; i < 31; ++i) {
+        n[i] = scalar[i];
+    }
+    n[31] = scalar[31] & 127;
+
+    /* private key: a = n + t */
+    if (private_key) {
+        sc_muladd(private_key, SC_1, n, private_key);
+
+        // https://github.com/orlp/ed25519/issues/3
+        sha512_init(&hash);
+        sha512_update(&hash, private_key + 32, 32);
+        sha512_update(&hash, scalar, 32);
+        sha512_final(&hash, hashbuf);
+        for (i = 0; i < 32; ++i) {
+            private_key[32 + i] = hashbuf[i];
+        }
+    }
+
+    /* public key: A = nB + T */
+    if (public_key) {
+        /* if we know the private key we don't need a point addition, which is faster */
+        /* using a "timing attack" you could find out wether or not we know the private
+           key, but this information seems rather useless - if this is important pass
+           public_key and private_key seperately in 2 function calls */
+        if (private_key) {
+            ge_scalarmult_base(&A, private_key);
+        } else {
+            /* unpack public key into T */
+            ge_frombytes_negate_vartime(&public_key_unpacked, public_key);
+            fe_neg(public_key_unpacked.X, public_key_unpacked.X); /* undo negate */
+            fe_neg(public_key_unpacked.T, public_key_unpacked.T); /* undo negate */
+            ge_p3_to_cached(&T, &public_key_unpacked);
+
+            /* calculate n*B */
+            ge_scalarmult_base(&nB, n);
+
+            /* A = n*B + T */
+            ge_add(&A_p1p1, &nB, &T);
+            ge_p1p1_to_p3(&A, &A_p1p1);
+        }
+            
+        /* pack public key */
+        ge_p3_tobytes(public_key, &A);
+    }
+}

lib/ed25519/ed_25519.h

@@ -0,0 +1,40 @@
+#ifndef ED25519_H
+#define ED25519_H
+
+// Nightcracker's Ed25519 -  https://github.com/orlp/ed25519
+
+#include <stddef.h>
+
+#if defined(_WIN32)
+    #if defined(ED25519_BUILD_DLL)
+        #define ED25519_DECLSPEC __declspec(dllexport)
+    #elif defined(ED25519_DLL)
+        #define ED25519_DECLSPEC __declspec(dllimport)
+    #else
+        #define ED25519_DECLSPEC
+    #endif
+#else
+    #define ED25519_DECLSPEC
+#endif
+
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#ifndef ED25519_NO_SEED
+int ED25519_DECLSPEC ed25519_create_seed(unsigned char *seed);
+#endif
+
+void ED25519_DECLSPEC ed25519_create_keypair(unsigned char *public_key, unsigned char *private_key, const unsigned char *seed);
+void ED25519_DECLSPEC ed25519_sign(unsigned char *signature, const unsigned char *message, size_t message_len, const unsigned char *public_key, const unsigned char *private_key);
+int ED25519_DECLSPEC ed25519_verify(const unsigned char *signature, const unsigned char *message, size_t message_len, const unsigned char *public_key);
+void ED25519_DECLSPEC ed25519_add_scalar(unsigned char *public_key, unsigned char *private_key, const unsigned char *scalar);
+void ED25519_DECLSPEC ed25519_key_exchange(unsigned char *shared_secret, const unsigned char *public_key, const unsigned char *private_key);
+
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif

lib/ed25519/fe.h

@@ -0,0 +1,41 @@
+#ifndef FE_H
+#define FE_H
+
+#include "fixedint.h"
+
+
+/*
+    fe means field element.
+    Here the field is \Z/(2^255-19).
+    An element t, entries t[0]...t[9], represents the integer
+    t[0]+2^26 t[1]+2^51 t[2]+2^77 t[3]+2^102 t[4]+...+2^230 t[9].
+    Bounds on each t[i] vary depending on context.
+*/
+
+
+typedef int32_t fe[10];
+
+
+void fe_0(fe h);
+void fe_1(fe h);
+
+void fe_frombytes(fe h, const unsigned char *s);
+void fe_tobytes(unsigned char *s, const fe h);
+
+void fe_copy(fe h, const fe f);
+int fe_isnegative(const fe f);
+int fe_isnonzero(const fe f);
+void fe_cmov(fe f, const fe g, unsigned int b);
+void fe_cswap(fe f, fe g, unsigned int b);
+
+void fe_neg(fe h, const fe f);
+void fe_add(fe h, const fe f, const fe g);
+void fe_invert(fe out, const fe z);
+void fe_sq(fe h, const fe f);
+void fe_sq2(fe h, const fe f);
+void fe_mul(fe h, const fe f, const fe g);
+void fe_mul121666(fe h, fe f);
+void fe_pow22523(fe out, const fe z);
+void fe_sub(fe h, const fe f, const fe g);
+
+#endif

lib/ed25519/fixedint.h

@@ -0,0 +1,72 @@
+/*
+    Portable header to provide the 32 and 64 bits type.
+
+    Not a compatible replacement for <stdint.h>, do not blindly use it as such.
+*/
+
+#if ((defined(__STDC__) && __STDC__ && __STDC_VERSION__ >= 199901L) || (defined(__WATCOMC__) && (defined(_STDINT_H_INCLUDED) || __WATCOMC__ >= 1250)) || (defined(__GNUC__) && (defined(_STDINT_H) || defined(_STDINT_H_) || defined(__UINT_FAST64_TYPE__)) )) && !defined(FIXEDINT_H_INCLUDED)
+    #include <stdint.h>
+    #define FIXEDINT_H_INCLUDED
+
+    #if defined(__WATCOMC__) && __WATCOMC__ >= 1250 && !defined(UINT64_C)
+        #include <limits.h>
+        #define UINT64_C(x) (x + (UINT64_MAX - UINT64_MAX))
+    #endif
+#endif
+
+
+#ifndef FIXEDINT_H_INCLUDED
+    #define FIXEDINT_H_INCLUDED
+    
+    #include <limits.h>
+
+    /* (u)int32_t */
+    #ifndef uint32_t
+        #if (ULONG_MAX == 0xffffffffUL)
+            typedef unsigned long uint32_t;
+        #elif (UINT_MAX == 0xffffffffUL)
+            typedef unsigned int uint32_t;
+        #elif (USHRT_MAX == 0xffffffffUL)
+            typedef unsigned short uint32_t;
+        #endif
+    #endif
+
+
+    #ifndef int32_t
+        #if (LONG_MAX == 0x7fffffffL)
+            typedef signed long int32_t;
+        #elif (INT_MAX == 0x7fffffffL)
+            typedef signed int int32_t;
+        #elif (SHRT_MAX == 0x7fffffffL)
+            typedef signed short int32_t;
+        #endif
+    #endif
+
+
+    /* (u)int64_t */
+    #if (defined(__STDC__) && defined(__STDC_VERSION__) && __STDC__ && __STDC_VERSION__ >= 199901L)
+        typedef long long int64_t;
+        typedef unsigned long long uint64_t;
+
+        #define UINT64_C(v) v ##ULL
+        #define INT64_C(v) v ##LL
+    #elif defined(__GNUC__)
+        __extension__ typedef long long int64_t;
+        __extension__ typedef unsigned long long uint64_t;
+
+        #define UINT64_C(v) v ##ULL
+        #define INT64_C(v) v ##LL
+    #elif defined(__MWERKS__) || defined(__SUNPRO_C) || defined(__SUNPRO_CC) || defined(__APPLE_CC__) || defined(_LONG_LONG) || defined(_CRAYC)
+        typedef long long int64_t;
+        typedef unsigned long long uint64_t;
+
+        #define UINT64_C(v) v ##ULL
+        #define INT64_C(v) v ##LL
+    #elif (defined(__WATCOMC__) && defined(__WATCOM_INT64__)) || (defined(_MSC_VER) && _INTEGRAL_MAX_BITS >= 64) || (defined(__BORLANDC__) && __BORLANDC__ > 0x460) || defined(__alpha) || defined(__DECC)
+        typedef __int64 int64_t;
+        typedef unsigned __int64 uint64_t;
+
+        #define UINT64_C(v) v ##UI64
+        #define INT64_C(v) v ##I64
+    #endif
+#endif

lib/ed25519/ge.c

@@ -0,0 +1,467 @@
+#include "ge.h"
+#include "precomp_data.h"
+
+
+/*
+r = p + q
+*/
+
+void ge_add(ge_p1p1 *r, const ge_p3 *p, const ge_cached *q) {
+    fe t0;
+    fe_add(r->X, p->Y, p->X);
+    fe_sub(r->Y, p->Y, p->X);
+    fe_mul(r->Z, r->X, q->YplusX);
+    fe_mul(r->Y, r->Y, q->YminusX);
+    fe_mul(r->T, q->T2d, p->T);
+    fe_mul(r->X, p->Z, q->Z);
+    fe_add(t0, r->X, r->X);
+    fe_sub(r->X, r->Z, r->Y);
+    fe_add(r->Y, r->Z, r->Y);
+    fe_add(r->Z, t0, r->T);
+    fe_sub(r->T, t0, r->T);
+}
+
+
+static void slide(signed char *r, const unsigned char *a) {
+    int i;
+    int b;
+    int k;
+
+    for (i = 0; i < 256; ++i) {
+        r[i] = 1 & (a[i >> 3] >> (i & 7));
+    }
+
+    for (i = 0; i < 256; ++i)
+        if (r[i]) {
+            for (b = 1; b <= 6 && i + b < 256; ++b) {
+                if (r[i + b]) {
+                    if (r[i] + (r[i + b] << b) <= 15) {
+                        r[i] += r[i + b] << b;
+                        r[i + b] = 0;
+                    } else if (r[i] - (r[i + b] << b) >= -15) {
+                        r[i] -= r[i + b] << b;
+
+                        for (k = i + b; k < 256; ++k) {
+                            if (!r[k]) {
+                                r[k] = 1;
+                                break;
+                            }
+
+                            r[k] = 0;
+                        }
+                    } else {
+                        break;
+                    }
+                }
+            }
+        }
+}
+
+/*
+r = a * A + b * B
+where a = a[0]+256*a[1]+...+256^31 a[31].
+and b = b[0]+256*b[1]+...+256^31 b[31].
+B is the Ed25519 base point (x,4/5) with x positive.
+*/
+
+void ge_double_scalarmult_vartime(ge_p2 *r, const unsigned char *a, const ge_p3 *A, const unsigned char *b) {
+    signed char aslide[256];
+    signed char bslide[256];
+    ge_cached Ai[8]; /* A,3A,5A,7A,9A,11A,13A,15A */
+    ge_p1p1 t;
+    ge_p3 u;
+    ge_p3 A2;
+    int i;
+    slide(aslide, a);
+    slide(bslide, b);
+    ge_p3_to_cached(&Ai[0], A);
+    ge_p3_dbl(&t, A);
+    ge_p1p1_to_p3(&A2, &t);
+    ge_add(&t, &A2, &Ai[0]);
+    ge_p1p1_to_p3(&u, &t);
+    ge_p3_to_cached(&Ai[1], &u);
+    ge_add(&t, &A2, &Ai[1]);
+    ge_p1p1_to_p3(&u, &t);
+    ge_p3_to_cached(&Ai[2], &u);
+    ge_add(&t, &A2, &Ai[2]);
+    ge_p1p1_to_p3(&u, &t);
+    ge_p3_to_cached(&Ai[3], &u);
+    ge_add(&t, &A2, &Ai[3]);
+    ge_p1p1_to_p3(&u, &t);
+    ge_p3_to_cached(&Ai[4], &u);
+    ge_add(&t, &A2, &Ai[4]);
+    ge_p1p1_to_p3(&u, &t);
+    ge_p3_to_cached(&Ai[5], &u);
+    ge_add(&t, &A2, &Ai[5]);
+    ge_p1p1_to_p3(&u, &t);
+    ge_p3_to_cached(&Ai[6], &u);
+    ge_add(&t, &A2, &Ai[6]);
+    ge_p1p1_to_p3(&u, &t);
+    ge_p3_to_cached(&Ai[7], &u);
+    ge_p2_0(r);
+
+    for (i = 255; i >= 0; --i) {
+        if (aslide[i] || bslide[i]) {
+            break;
+        }
+    }
+
+    for (; i >= 0; --i) {
+        ge_p2_dbl(&t, r);
+
+        if (aslide[i] > 0) {
+            ge_p1p1_to_p3(&u, &t);
+            ge_add(&t, &u, &Ai[aslide[i] / 2]);
+        } else if (aslide[i] < 0) {
+            ge_p1p1_to_p3(&u, &t);
+            ge_sub(&t, &u, &Ai[(-aslide[i]) / 2]);
+        }
+
+        if (bslide[i] > 0) {
+            ge_p1p1_to_p3(&u, &t);
+            ge_madd(&t, &u, &Bi[bslide[i] / 2]);
+        } else if (bslide[i] < 0) {
+            ge_p1p1_to_p3(&u, &t);
+            ge_msub(&t, &u, &Bi[(-bslide[i]) / 2]);
+        }
+
+        ge_p1p1_to_p2(r, &t);
+    }
+}
+
+
+static const fe d = {
+    -10913610, 13857413, -15372611, 6949391, 114729, -8787816, -6275908, -3247719, -18696448, -12055116
+};
+
+static const fe sqrtm1 = {
+    -32595792, -7943725, 9377950, 3500415, 12389472, -272473, -25146209, -2005654, 326686, 11406482
+};
+
+int ge_frombytes_negate_vartime(ge_p3 *h, const unsigned char *s) {
+    fe u;
+    fe v;
+    fe v3;
+    fe vxx;
+    fe check;
+    fe_frombytes(h->Y, s);
+    fe_1(h->Z);
+    fe_sq(u, h->Y);
+    fe_mul(v, u, d);
+    fe_sub(u, u, h->Z);     /* u = y^2-1 */
+    fe_add(v, v, h->Z);     /* v = dy^2+1 */
+    fe_sq(v3, v);
+    fe_mul(v3, v3, v);      /* v3 = v^3 */
+    fe_sq(h->X, v3);
+    fe_mul(h->X, h->X, v);
+    fe_mul(h->X, h->X, u);  /* x = uv^7 */
+    fe_pow22523(h->X, h->X); /* x = (uv^7)^((q-5)/8) */
+    fe_mul(h->X, h->X, v3);
+    fe_mul(h->X, h->X, u);  /* x = uv^3(uv^7)^((q-5)/8) */
+    fe_sq(vxx, h->X);
+    fe_mul(vxx, vxx, v);
+    fe_sub(check, vxx, u);  /* vx^2-u */
+
+    if (fe_isnonzero(check)) {
+        fe_add(check, vxx, u); /* vx^2+u */
+
+        if (fe_isnonzero(check)) {
+            return -1;
+        }
+
+        fe_mul(h->X, h->X, sqrtm1);
+    }
+
+    if (fe_isnegative(h->X) == (s[31] >> 7)) {
+        fe_neg(h->X, h->X);
+    }
+
+    fe_mul(h->T, h->X, h->Y);
+    return 0;
+}
+
+
+/*
+r = p + q
+*/
+
+void ge_madd(ge_p1p1 *r, const ge_p3 *p, const ge_precomp *q) {
+    fe t0;
+    fe_add(r->X, p->Y, p->X);
+    fe_sub(r->Y, p->Y, p->X);
+    fe_mul(r->Z, r->X, q->yplusx);
+    fe_mul(r->Y, r->Y, q->yminusx);
+    fe_mul(r->T, q->xy2d, p->T);
+    fe_add(t0, p->Z, p->Z);
+    fe_sub(r->X, r->Z, r->Y);
+    fe_add(r->Y, r->Z, r->Y);
+    fe_add(r->Z, t0, r->T);
+    fe_sub(r->T, t0, r->T);
+}
+
+
+/*
+r = p - q
+*/
+
+void ge_msub(ge_p1p1 *r, const ge_p3 *p, const ge_precomp *q) {
+    fe t0;
+
+    fe_add(r->X, p->Y, p->X);
+    fe_sub(r->Y, p->Y, p->X);
+    fe_mul(r->Z, r->X, q->yminusx);
+    fe_mul(r->Y, r->Y, q->yplusx);
+    fe_mul(r->T, q->xy2d, p->T);
+    fe_add(t0, p->Z, p->Z);
+    fe_sub(r->X, r->Z, r->Y);
+    fe_add(r->Y, r->Z, r->Y);
+    fe_sub(r->Z, t0, r->T);
+    fe_add(r->T, t0, r->T);
+}
+
+
+/*
+r = p
+*/
+
+void ge_p1p1_to_p2(ge_p2 *r, const ge_p1p1 *p) {
+    fe_mul(r->X, p->X, p->T);
+    fe_mul(r->Y, p->Y, p->Z);
+    fe_mul(r->Z, p->Z, p->T);
+}
+
+
+
+/*
+r = p
+*/
+
+void ge_p1p1_to_p3(ge_p3 *r, const ge_p1p1 *p) {
+    fe_mul(r->X, p->X, p->T);
+    fe_mul(r->Y, p->Y, p->Z);
+    fe_mul(r->Z, p->Z, p->T);
+    fe_mul(r->T, p->X, p->Y);
+}
+
+
+void ge_p2_0(ge_p2 *h) {
+    fe_0(h->X);
+    fe_1(h->Y);
+    fe_1(h->Z);
+}
+
+
+
+/*
+r = 2 * p
+*/
+
+void ge_p2_dbl(ge_p1p1 *r, const ge_p2 *p) {
+    fe t0;
+
+    fe_sq(r->X, p->X);
+    fe_sq(r->Z, p->Y);
+    fe_sq2(r->T, p->Z);
+    fe_add(r->Y, p->X, p->Y);
+    fe_sq(t0, r->Y);
+    fe_add(r->Y, r->Z, r->X);
+    fe_sub(r->Z, r->Z, r->X);
+    fe_sub(r->X, t0, r->Y);
+    fe_sub(r->T, r->T, r->Z);
+}
+
+
+void ge_p3_0(ge_p3 *h) {
+    fe_0(h->X);
+    fe_1(h->Y);
+    fe_1(h->Z);
+    fe_0(h->T);
+}
+
+
+/*
+r = 2 * p
+*/
+
+void ge_p3_dbl(ge_p1p1 *r, const ge_p3 *p) {
+    ge_p2 q;
+    ge_p3_to_p2(&q, p);
+    ge_p2_dbl(r, &q);
+}
+
+
+
+/*
+r = p
+*/
+
+static const fe d2 = {
+    -21827239, -5839606, -30745221, 13898782, 229458, 15978800, -12551817, -6495438, 29715968, 9444199
+};
+
+void ge_p3_to_cached(ge_cached *r, const ge_p3 *p) {
+    fe_add(r->YplusX, p->Y, p->X);
+    fe_sub(r->YminusX, p->Y, p->X);
+    fe_copy(r->Z, p->Z);
+    fe_mul(r->T2d, p->T, d2);
+}
+
+
+/*
+r = p
+*/
+
+void ge_p3_to_p2(ge_p2 *r, const ge_p3 *p) {
+    fe_copy(r->X, p->X);
+    fe_copy(r->Y, p->Y);
+    fe_copy(r->Z, p->Z);
+}
+
+
+void ge_p3_tobytes(unsigned char *s, const ge_p3 *h) {
+    fe recip;
+    fe x;
+    fe y;
+    fe_invert(recip, h->Z);
+    fe_mul(x, h->X, recip);
+    fe_mul(y, h->Y, recip);
+    fe_tobytes(s, y);
+    s[31] ^= fe_isnegative(x) << 7;
+}
+
+
+static unsigned char equal(signed char b, signed char c) {
+    unsigned char ub = b;
+    unsigned char uc = c;
+    unsigned char x = ub ^ uc; /* 0: yes; 1..255: no */
+    uint64_t y = x; /* 0: yes; 1..255: no */
+    y -= 1; /* large: yes; 0..254: no */
+    y >>= 63; /* 1: yes; 0: no */
+    return (unsigned char) y;
+}
+
+static unsigned char negative(signed char b) {
+    uint64_t x = b; /* 18446744073709551361..18446744073709551615: yes; 0..255: no */
+    x >>= 63; /* 1: yes; 0: no */
+    return (unsigned char) x;
+}
+
+static void cmov(ge_precomp *t, const ge_precomp *u, unsigned char b) {
+    fe_cmov(t->yplusx, u->yplusx, b);
+    fe_cmov(t->yminusx, u->yminusx, b);
+    fe_cmov(t->xy2d, u->xy2d, b);
+}
+
+
+static void select(ge_precomp *t, int pos, signed char b) {
+    ge_precomp minust;
+    unsigned char bnegative = negative(b);
+    unsigned char babs = b - (((-bnegative) & b) << 1);
+    fe_1(t->yplusx);
+    fe_1(t->yminusx);
+    fe_0(t->xy2d);
+    cmov(t, &base[pos][0], equal(babs, 1));
+    cmov(t, &base[pos][1], equal(babs, 2));
+    cmov(t, &base[pos][2], equal(babs, 3));
+    cmov(t, &base[pos][3], equal(babs, 4));
+    cmov(t, &base[pos][4], equal(babs, 5));
+    cmov(t, &base[pos][5], equal(babs, 6));
+    cmov(t, &base[pos][6], equal(babs, 7));
+    cmov(t, &base[pos][7], equal(babs, 8));
+    fe_copy(minust.yplusx, t->yminusx);
+    fe_copy(minust.yminusx, t->yplusx);
+    fe_neg(minust.xy2d, t->xy2d);
+    cmov(t, &minust, bnegative);
+}
+
+/*
+h = a * B
+where a = a[0]+256*a[1]+...+256^31 a[31]
+B is the Ed25519 base point (x,4/5) with x positive.
+
+Preconditions:
+  a[31] <= 127
+*/
+
+void ge_scalarmult_base(ge_p3 *h, const unsigned char *a) {
+    signed char e[64];
+    signed char carry;
+    ge_p1p1 r;
+    ge_p2 s;
+    ge_precomp t;
+    int i;
+
+    for (i = 0; i < 32; ++i) {
+        e[2 * i + 0] = (a[i] >> 0) & 15;
+        e[2 * i + 1] = (a[i] >> 4) & 15;
+    }
+
+    /* each e[i] is between 0 and 15 */
+    /* e[63] is between 0 and 7 */
+    carry = 0;
+
+    for (i = 0; i < 63; ++i) {
+        e[i] += carry;
+        carry = e[i] + 8;
+        carry >>= 4;
+        e[i] -= carry << 4;
+    }
+
+    e[63] += carry;
+    /* each e[i] is between -8 and 8 */
+    ge_p3_0(h);
+
+    for (i = 1; i < 64; i += 2) {
+        select(&t, i / 2, e[i]);
+        ge_madd(&r, h, &t);
+        ge_p1p1_to_p3(h, &r);
+    }
+
+    ge_p3_dbl(&r, h);
+    ge_p1p1_to_p2(&s, &r);
+    ge_p2_dbl(&r, &s);
+    ge_p1p1_to_p2(&s, &r);
+    ge_p2_dbl(&r, &s);
+    ge_p1p1_to_p2(&s, &r);
+    ge_p2_dbl(&r, &s);
+    ge_p1p1_to_p3(h, &r);
+
+    for (i = 0; i < 64; i += 2) {
+        select(&t, i / 2, e[i]);
+        ge_madd(&r, h, &t);
+        ge_p1p1_to_p3(h, &r);
+    }
+}
+
+
+/*
+r = p - q
+*/
+
+void ge_sub(ge_p1p1 *r, const ge_p3 *p, const ge_cached *q) {
+    fe t0;
+    
+    fe_add(r->X, p->Y, p->X);
+    fe_sub(r->Y, p->Y, p->X);
+    fe_mul(r->Z, r->X, q->YminusX);
+    fe_mul(r->Y, r->Y, q->YplusX);
+    fe_mul(r->T, q->T2d, p->T);
+    fe_mul(r->X, p->Z, q->Z);
+    fe_add(t0, r->X, r->X);
+    fe_sub(r->X, r->Z, r->Y);
+    fe_add(r->Y, r->Z, r->Y);
+    fe_sub(r->Z, t0, r->T);
+    fe_add(r->T, t0, r->T);
+}
+
+
+void ge_tobytes(unsigned char *s, const ge_p2 *h) {
+    fe recip;
+    fe x;
+    fe y;
+    fe_invert(recip, h->Z);
+    fe_mul(x, h->X, recip);
+    fe_mul(y, h->Y, recip);
+    fe_tobytes(s, y);
+    s[31] ^= fe_isnegative(x) << 7;
+}

lib/ed25519/ge.h

@@ -0,0 +1,74 @@
+#ifndef GE_H
+#define GE_H
+
+#include "fe.h"
+
+
+/*
+ge means group element.
+
+Here the group is the set of pairs (x,y) of field elements (see fe.h)
+satisfying -x^2 + y^2 = 1 + d x^2y^2
+where d = -121665/121666.
+
+Representations:
+  ge_p2 (projective): (X:Y:Z) satisfying x=X/Z, y=Y/Z
+  ge_p3 (extended): (X:Y:Z:T) satisfying x=X/Z, y=Y/Z, XY=ZT
+  ge_p1p1 (completed): ((X:Z),(Y:T)) satisfying x=X/Z, y=Y/T
+  ge_precomp (Duif): (y+x,y-x,2dxy)
+*/
+
+typedef struct {
+  fe X;
+  fe Y;
+  fe Z;
+} ge_p2;
+
+typedef struct {
+  fe X;
+  fe Y;
+  fe Z;
+  fe T;
+} ge_p3;
+
+typedef struct {
+  fe X;
+  fe Y;
+  fe Z;
+  fe T;
+} ge_p1p1;
+
+typedef struct {
+  fe yplusx;
+  fe yminusx;
+  fe xy2d;
+} ge_precomp;
+
+typedef struct {
+  fe YplusX;
+  fe YminusX;
+  fe Z;
+  fe T2d;
+} ge_cached;
+
+void ge_p3_tobytes(unsigned char *s, const ge_p3 *h);
+void ge_tobytes(unsigned char *s, const ge_p2 *h);
+int ge_frombytes_negate_vartime(ge_p3 *h, const unsigned char *s);
+
+void ge_add(ge_p1p1 *r, const ge_p3 *p, const ge_cached *q);
+void ge_sub(ge_p1p1 *r, const ge_p3 *p, const ge_cached *q);
+void ge_double_scalarmult_vartime(ge_p2 *r, const unsigned char *a, const ge_p3 *A, const unsigned char *b);
+void ge_madd(ge_p1p1 *r, const ge_p3 *p, const ge_precomp *q);
+void ge_msub(ge_p1p1 *r, const ge_p3 *p, const ge_precomp *q);
+void ge_scalarmult_base(ge_p3 *h, const unsigned char *a);
+
+void ge_p1p1_to_p2(ge_p2 *r, const ge_p1p1 *p);
+void ge_p1p1_to_p3(ge_p3 *r, const ge_p1p1 *p);
+void ge_p2_0(ge_p2 *h);
+void ge_p2_dbl(ge_p1p1 *r, const ge_p2 *p);
+void ge_p3_0(ge_p3 *h);
+void ge_p3_dbl(ge_p1p1 *r, const ge_p3 *p);
+void ge_p3_to_cached(ge_cached *r, const ge_p3 *p);
+void ge_p3_to_p2(ge_p2 *r, const ge_p3 *p);
+
+#endif

lib/ed25519/key_exchange.c

@@ -0,0 +1,79 @@
+#include "ed_25519.h"
+#include "fe.h"
+
+void ed25519_key_exchange(unsigned char *shared_secret, const unsigned char *public_key, const unsigned char *private_key) {
+    unsigned char e[32];
+    unsigned int i;
+    
+    fe x1;
+    fe x2;
+    fe z2;
+    fe x3;
+    fe z3;
+    fe tmp0;
+    fe tmp1;
+
+    int pos;
+    unsigned int swap;
+    unsigned int b;
+
+    /* copy the private key and make sure it's valid */
+    for (i = 0; i < 32; ++i) {
+        e[i] = private_key[i];
+    }
+
+    e[0] &= 248;
+    e[31] &= 63;
+    e[31] |= 64;
+
+    /* unpack the public key and convert edwards to montgomery */
+    /* due to CodesInChaos: montgomeryX = (edwardsY + 1)*inverse(1 - edwardsY) mod p */
+    fe_frombytes(x1, public_key);
+    fe_1(tmp1);
+    fe_add(tmp0, x1, tmp1);
+    fe_sub(tmp1, tmp1, x1);
+    fe_invert(tmp1, tmp1);
+    fe_mul(x1, tmp0, tmp1);
+
+    fe_1(x2);
+    fe_0(z2);
+    fe_copy(x3, x1);
+    fe_1(z3);
+
+    swap = 0;
+    for (pos = 254; pos >= 0; --pos) {
+        b = e[pos / 8] >> (pos & 7);
+        b &= 1;
+        swap ^= b;
+        fe_cswap(x2, x3, swap);
+        fe_cswap(z2, z3, swap);
+        swap = b;
+
+        /* from montgomery.h */
+        fe_sub(tmp0, x3, z3);
+        fe_sub(tmp1, x2, z2);
+        fe_add(x2, x2, z2);
+        fe_add(z2, x3, z3);
+        fe_mul(z3, tmp0, x2);
+        fe_mul(z2, z2, tmp1);
+        fe_sq(tmp0, tmp1);
+        fe_sq(tmp1, x2);
+        fe_add(x3, z3, z2);
+        fe_sub(z2, z3, z2);
+        fe_mul(x2, tmp1, tmp0);
+        fe_sub(tmp1, tmp1, tmp0);
+        fe_sq(z2, z2);
+        fe_mul121666(z3, tmp1);
+        fe_sq(x3, x3);
+        fe_add(tmp0, tmp0, z3);
+        fe_mul(z3, x1, z2);
+        fe_mul(z2, tmp1, tmp0);
+    }
+
+    fe_cswap(x2, x3, swap);
+    fe_cswap(z2, z3, swap);
+
+    fe_invert(z2, z2);
+    fe_mul(x2, x2, z2);
+    fe_tobytes(shared_secret, x2);
+}

lib/ed25519/keypair.c

@@ -0,0 +1,16 @@
+#include "ed_25519.h"
+#include "sha512.h"
+#include "ge.h"
+
+
+void ed25519_create_keypair(unsigned char *public_key, unsigned char *private_key, const unsigned char *seed) {
+    ge_p3 A;
+
+    sha512(seed, 32, private_key);
+    private_key[0] &= 248;
+    private_key[31] &= 63;
+    private_key[31] |= 64;
+
+    ge_scalarmult_base(&A, private_key);
+    ge_p3_tobytes(public_key, &A);
+}

lib/ed25519/license.txt

@@ -0,0 +1,16 @@
+Copyright (c) 2015 Orson Peters <[email protected]>
+
+This software is provided 'as-is', without any express or implied warranty. In no event will the
+authors be held liable for any damages arising from the use of this software.
+
+Permission is granted to anyone to use this software for any purpose, including commercial
+applications, and to alter it and redistribute it freely, subject to the following restrictions:
+
+1. The origin of this software must not be misrepresented; you must not claim that you wrote the
+   original software. If you use this software in a product, an acknowledgment in the product
+   documentation would be appreciated but is not required.
+
+2. Altered source versions must be plainly marked as such, and must not be misrepresented as
+   being the original software.
+
+3. This notice may not be removed or altered from any source distribution.

lib/ed25519/sc.c

@@ -0,0 +1,809 @@
+#include "fixedint.h"
+#include "sc.h"
+
+static uint64_t load_3(const unsigned char *in) {
+    uint64_t result;
+
+    result = (uint64_t) in[0];
+    result |= ((uint64_t) in[1]) << 8;
+    result |= ((uint64_t) in[2]) << 16;
+
+    return result;
+}
+
+static uint64_t load_4(const unsigned char *in) {
+    uint64_t result;
+
+    result = (uint64_t) in[0];
+    result |= ((uint64_t) in[1]) << 8;
+    result |= ((uint64_t) in[2]) << 16;
+    result |= ((uint64_t) in[3]) << 24;
+    
+    return result;
+}
+
+/*
+Input:
+  s[0]+256*s[1]+...+256^63*s[63] = s
+
+Output:
+  s[0]+256*s[1]+...+256^31*s[31] = s mod l
+  where l = 2^252 + 27742317777372353535851937790883648493.
+  Overwrites s in place.
+*/
+
+void sc_reduce(unsigned char *s) {
+    int64_t s0 = 2097151 & load_3(s);
+    int64_t s1 = 2097151 & (load_4(s + 2) >> 5);
+    int64_t s2 = 2097151 & (load_3(s + 5) >> 2);
+    int64_t s3 = 2097151 & (load_4(s + 7) >> 7);
+    int64_t s4 = 2097151 & (load_4(s + 10) >> 4);
+    int64_t s5 = 2097151 & (load_3(s + 13) >> 1);
+    int64_t s6 = 2097151 & (load_4(s + 15) >> 6);
+    int64_t s7 = 2097151 & (load_3(s + 18) >> 3);
+    int64_t s8 = 2097151 & load_3(s + 21);
+    int64_t s9 = 2097151 & (load_4(s + 23) >> 5);
+    int64_t s10 = 2097151 & (load_3(s + 26) >> 2);
+    int64_t s11 = 2097151 & (load_4(s + 28) >> 7);
+    int64_t s12 = 2097151 & (load_4(s + 31) >> 4);
+    int64_t s13 = 2097151 & (load_3(s + 34) >> 1);
+    int64_t s14 = 2097151 & (load_4(s + 36) >> 6);
+    int64_t s15 = 2097151 & (load_3(s + 39) >> 3);
+    int64_t s16 = 2097151 & load_3(s + 42);
+    int64_t s17 = 2097151 & (load_4(s + 44) >> 5);
+    int64_t s18 = 2097151 & (load_3(s + 47) >> 2);
+    int64_t s19 = 2097151 & (load_4(s + 49) >> 7);
+    int64_t s20 = 2097151 & (load_4(s + 52) >> 4);
+    int64_t s21 = 2097151 & (load_3(s + 55) >> 1);
+    int64_t s22 = 2097151 & (load_4(s + 57) >> 6);
+    int64_t s23 = (load_4(s + 60) >> 3);
+    int64_t carry0;
+    int64_t carry1;
+    int64_t carry2;
+    int64_t carry3;
+    int64_t carry4;
+    int64_t carry5;
+    int64_t carry6;
+    int64_t carry7;
+    int64_t carry8;
+    int64_t carry9;
+    int64_t carry10;
+    int64_t carry11;
+    int64_t carry12;
+    int64_t carry13;
+    int64_t carry14;
+    int64_t carry15;
+    int64_t carry16;
+
+    s11 += s23 * 666643;
+    s12 += s23 * 470296;
+    s13 += s23 * 654183;
+    s14 -= s23 * 997805;
+    s15 += s23 * 136657;
+    s16 -= s23 * 683901;
+    s23 = 0;
+    s10 += s22 * 666643;
+    s11 += s22 * 470296;
+    s12 += s22 * 654183;
+    s13 -= s22 * 997805;
+    s14 += s22 * 136657;
+    s15 -= s22 * 683901;
+    s22 = 0;
+    s9 += s21 * 666643;
+    s10 += s21 * 470296;
+    s11 += s21 * 654183;
+    s12 -= s21 * 997805;
+    s13 += s21 * 136657;
+    s14 -= s21 * 683901;
+    s21 = 0;
+    s8 += s20 * 666643;
+    s9 += s20 * 470296;
+    s10 += s20 * 654183;
+    s11 -= s20 * 997805;
+    s12 += s20 * 136657;
+    s13 -= s20 * 683901;
+    s20 = 0;
+    s7 += s19 * 666643;
+    s8 += s19 * 470296;
+    s9 += s19 * 654183;
+    s10 -= s19 * 997805;
+    s11 += s19 * 136657;
+    s12 -= s19 * 683901;
+    s19 = 0;
+    s6 += s18 * 666643;
+    s7 += s18 * 470296;
+    s8 += s18 * 654183;
+    s9 -= s18 * 997805;
+    s10 += s18 * 136657;
+    s11 -= s18 * 683901;
+    s18 = 0;
+    carry6 = (s6 + (1 << 20)) >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry8 = (s8 + (1 << 20)) >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry10 = (s10 + (1 << 20)) >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+    carry12 = (s12 + (1 << 20)) >> 21;
+    s13 += carry12;
+    s12 -= carry12 << 21;
+    carry14 = (s14 + (1 << 20)) >> 21;
+    s15 += carry14;
+    s14 -= carry14 << 21;
+    carry16 = (s16 + (1 << 20)) >> 21;
+    s17 += carry16;
+    s16 -= carry16 << 21;
+    carry7 = (s7 + (1 << 20)) >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry9 = (s9 + (1 << 20)) >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry11 = (s11 + (1 << 20)) >> 21;
+    s12 += carry11;
+    s11 -= carry11 << 21;
+    carry13 = (s13 + (1 << 20)) >> 21;
+    s14 += carry13;
+    s13 -= carry13 << 21;
+    carry15 = (s15 + (1 << 20)) >> 21;
+    s16 += carry15;
+    s15 -= carry15 << 21;
+    s5 += s17 * 666643;
+    s6 += s17 * 470296;
+    s7 += s17 * 654183;
+    s8 -= s17 * 997805;
+    s9 += s17 * 136657;
+    s10 -= s17 * 683901;
+    s17 = 0;
+    s4 += s16 * 666643;
+    s5 += s16 * 470296;
+    s6 += s16 * 654183;
+    s7 -= s16 * 997805;
+    s8 += s16 * 136657;
+    s9 -= s16 * 683901;
+    s16 = 0;
+    s3 += s15 * 666643;
+    s4 += s15 * 470296;
+    s5 += s15 * 654183;
+    s6 -= s15 * 997805;
+    s7 += s15 * 136657;
+    s8 -= s15 * 683901;
+    s15 = 0;
+    s2 += s14 * 666643;
+    s3 += s14 * 470296;
+    s4 += s14 * 654183;
+    s5 -= s14 * 997805;
+    s6 += s14 * 136657;
+    s7 -= s14 * 683901;
+    s14 = 0;
+    s1 += s13 * 666643;
+    s2 += s13 * 470296;
+    s3 += s13 * 654183;
+    s4 -= s13 * 997805;
+    s5 += s13 * 136657;
+    s6 -= s13 * 683901;
+    s13 = 0;
+    s0 += s12 * 666643;
+    s1 += s12 * 470296;
+    s2 += s12 * 654183;
+    s3 -= s12 * 997805;
+    s4 += s12 * 136657;
+    s5 -= s12 * 683901;
+    s12 = 0;
+    carry0 = (s0 + (1 << 20)) >> 21;
+    s1 += carry0;
+    s0 -= carry0 << 21;
+    carry2 = (s2 + (1 << 20)) >> 21;
+    s3 += carry2;
+    s2 -= carry2 << 21;
+    carry4 = (s4 + (1 << 20)) >> 21;
+    s5 += carry4;
+    s4 -= carry4 << 21;
+    carry6 = (s6 + (1 << 20)) >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry8 = (s8 + (1 << 20)) >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry10 = (s10 + (1 << 20)) >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+    carry1 = (s1 + (1 << 20)) >> 21;
+    s2 += carry1;
+    s1 -= carry1 << 21;
+    carry3 = (s3 + (1 << 20)) >> 21;
+    s4 += carry3;
+    s3 -= carry3 << 21;
+    carry5 = (s5 + (1 << 20)) >> 21;
+    s6 += carry5;
+    s5 -= carry5 << 21;
+    carry7 = (s7 + (1 << 20)) >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry9 = (s9 + (1 << 20)) >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry11 = (s11 + (1 << 20)) >> 21;
+    s12 += carry11;
+    s11 -= carry11 << 21;
+    s0 += s12 * 666643;
+    s1 += s12 * 470296;
+    s2 += s12 * 654183;
+    s3 -= s12 * 997805;
+    s4 += s12 * 136657;
+    s5 -= s12 * 683901;
+    s12 = 0;
+    carry0 = s0 >> 21;
+    s1 += carry0;
+    s0 -= carry0 << 21;
+    carry1 = s1 >> 21;
+    s2 += carry1;
+    s1 -= carry1 << 21;
+    carry2 = s2 >> 21;
+    s3 += carry2;
+    s2 -= carry2 << 21;
+    carry3 = s3 >> 21;
+    s4 += carry3;
+    s3 -= carry3 << 21;
+    carry4 = s4 >> 21;
+    s5 += carry4;
+    s4 -= carry4 << 21;
+    carry5 = s5 >> 21;
+    s6 += carry5;
+    s5 -= carry5 << 21;
+    carry6 = s6 >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry7 = s7 >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry8 = s8 >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry9 = s9 >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry10 = s10 >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+    carry11 = s11 >> 21;
+    s12 += carry11;
+    s11 -= carry11 << 21;
+    s0 += s12 * 666643;
+    s1 += s12 * 470296;
+    s2 += s12 * 654183;
+    s3 -= s12 * 997805;
+    s4 += s12 * 136657;
+    s5 -= s12 * 683901;
+    s12 = 0;
+    carry0 = s0 >> 21;
+    s1 += carry0;
+    s0 -= carry0 << 21;
+    carry1 = s1 >> 21;
+    s2 += carry1;
+    s1 -= carry1 << 21;
+    carry2 = s2 >> 21;
+    s3 += carry2;
+    s2 -= carry2 << 21;
+    carry3 = s3 >> 21;
+    s4 += carry3;
+    s3 -= carry3 << 21;
+    carry4 = s4 >> 21;
+    s5 += carry4;
+    s4 -= carry4 << 21;
+    carry5 = s5 >> 21;
+    s6 += carry5;
+    s5 -= carry5 << 21;
+    carry6 = s6 >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry7 = s7 >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry8 = s8 >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry9 = s9 >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry10 = s10 >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+
+    s[0] = (unsigned char) (s0 >> 0);
+    s[1] = (unsigned char) (s0 >> 8);
+    s[2] = (unsigned char) ((s0 >> 16) | (s1 << 5));
+    s[3] = (unsigned char) (s1 >> 3);
+    s[4] = (unsigned char) (s1 >> 11);
+    s[5] = (unsigned char) ((s1 >> 19) | (s2 << 2));
+    s[6] = (unsigned char) (s2 >> 6);
+    s[7] = (unsigned char) ((s2 >> 14) | (s3 << 7));
+    s[8] = (unsigned char) (s3 >> 1);
+    s[9] = (unsigned char) (s3 >> 9);
+    s[10] = (unsigned char) ((s3 >> 17) | (s4 << 4));
+    s[11] = (unsigned char) (s4 >> 4);
+    s[12] = (unsigned char) (s4 >> 12);
+    s[13] = (unsigned char) ((s4 >> 20) | (s5 << 1));
+    s[14] = (unsigned char) (s5 >> 7);
+    s[15] = (unsigned char) ((s5 >> 15) | (s6 << 6));
+    s[16] = (unsigned char) (s6 >> 2);
+    s[17] = (unsigned char) (s6 >> 10);
+    s[18] = (unsigned char) ((s6 >> 18) | (s7 << 3));
+    s[19] = (unsigned char) (s7 >> 5);
+    s[20] = (unsigned char) (s7 >> 13);
+    s[21] = (unsigned char) (s8 >> 0);
+    s[22] = (unsigned char) (s8 >> 8);
+    s[23] = (unsigned char) ((s8 >> 16) | (s9 << 5));
+    s[24] = (unsigned char) (s9 >> 3);
+    s[25] = (unsigned char) (s9 >> 11);
+    s[26] = (unsigned char) ((s9 >> 19) | (s10 << 2));
+    s[27] = (unsigned char) (s10 >> 6);
+    s[28] = (unsigned char) ((s10 >> 14) | (s11 << 7));
+    s[29] = (unsigned char) (s11 >> 1);
+    s[30] = (unsigned char) (s11 >> 9);
+    s[31] = (unsigned char) (s11 >> 17);
+}
+
+
+
+/*
+Input:
+  a[0]+256*a[1]+...+256^31*a[31] = a
+  b[0]+256*b[1]+...+256^31*b[31] = b
+  c[0]+256*c[1]+...+256^31*c[31] = c
+
+Output:
+  s[0]+256*s[1]+...+256^31*s[31] = (ab+c) mod l
+  where l = 2^252 + 27742317777372353535851937790883648493.
+*/
+
+void sc_muladd(unsigned char *s, const unsigned char *a, const unsigned char *b, const unsigned char *c) {
+    int64_t a0 = 2097151 & load_3(a);
+    int64_t a1 = 2097151 & (load_4(a + 2) >> 5);
+    int64_t a2 = 2097151 & (load_3(a + 5) >> 2);
+    int64_t a3 = 2097151 & (load_4(a + 7) >> 7);
+    int64_t a4 = 2097151 & (load_4(a + 10) >> 4);
+    int64_t a5 = 2097151 & (load_3(a + 13) >> 1);
+    int64_t a6 = 2097151 & (load_4(a + 15) >> 6);
+    int64_t a7 = 2097151 & (load_3(a + 18) >> 3);
+    int64_t a8 = 2097151 & load_3(a + 21);
+    int64_t a9 = 2097151 & (load_4(a + 23) >> 5);
+    int64_t a10 = 2097151 & (load_3(a + 26) >> 2);
+    int64_t a11 = (load_4(a + 28) >> 7);
+    int64_t b0 = 2097151 & load_3(b);
+    int64_t b1 = 2097151 & (load_4(b + 2) >> 5);
+    int64_t b2 = 2097151 & (load_3(b + 5) >> 2);
+    int64_t b3 = 2097151 & (load_4(b + 7) >> 7);
+    int64_t b4 = 2097151 & (load_4(b + 10) >> 4);
+    int64_t b5 = 2097151 & (load_3(b + 13) >> 1);
+    int64_t b6 = 2097151 & (load_4(b + 15) >> 6);
+    int64_t b7 = 2097151 & (load_3(b + 18) >> 3);
+    int64_t b8 = 2097151 & load_3(b + 21);
+    int64_t b9 = 2097151 & (load_4(b + 23) >> 5);
+    int64_t b10 = 2097151 & (load_3(b + 26) >> 2);
+    int64_t b11 = (load_4(b + 28) >> 7);
+    int64_t c0 = 2097151 & load_3(c);
+    int64_t c1 = 2097151 & (load_4(c + 2) >> 5);
+    int64_t c2 = 2097151 & (load_3(c + 5) >> 2);
+    int64_t c3 = 2097151 & (load_4(c + 7) >> 7);
+    int64_t c4 = 2097151 & (load_4(c + 10) >> 4);
+    int64_t c5 = 2097151 & (load_3(c + 13) >> 1);
+    int64_t c6 = 2097151 & (load_4(c + 15) >> 6);
+    int64_t c7 = 2097151 & (load_3(c + 18) >> 3);
+    int64_t c8 = 2097151 & load_3(c + 21);
+    int64_t c9 = 2097151 & (load_4(c + 23) >> 5);
+    int64_t c10 = 2097151 & (load_3(c + 26) >> 2);
+    int64_t c11 = (load_4(c + 28) >> 7);
+    int64_t s0;
+    int64_t s1;
+    int64_t s2;
+    int64_t s3;
+    int64_t s4;
+    int64_t s5;
+    int64_t s6;
+    int64_t s7;
+    int64_t s8;
+    int64_t s9;
+    int64_t s10;
+    int64_t s11;
+    int64_t s12;
+    int64_t s13;
+    int64_t s14;
+    int64_t s15;
+    int64_t s16;
+    int64_t s17;
+    int64_t s18;
+    int64_t s19;
+    int64_t s20;
+    int64_t s21;
+    int64_t s22;
+    int64_t s23;
+    int64_t carry0;
+    int64_t carry1;
+    int64_t carry2;
+    int64_t carry3;
+    int64_t carry4;
+    int64_t carry5;
+    int64_t carry6;
+    int64_t carry7;
+    int64_t carry8;
+    int64_t carry9;
+    int64_t carry10;
+    int64_t carry11;
+    int64_t carry12;
+    int64_t carry13;
+    int64_t carry14;
+    int64_t carry15;
+    int64_t carry16;
+    int64_t carry17;
+    int64_t carry18;
+    int64_t carry19;
+    int64_t carry20;
+    int64_t carry21;
+    int64_t carry22;
+
+    s0 = c0 + a0 * b0;
+    s1 = c1 + a0 * b1 + a1 * b0;
+    s2 = c2 + a0 * b2 + a1 * b1 + a2 * b0;
+    s3 = c3 + a0 * b3 + a1 * b2 + a2 * b1 + a3 * b0;
+    s4 = c4 + a0 * b4 + a1 * b3 + a2 * b2 + a3 * b1 + a4 * b0;
+    s5 = c5 + a0 * b5 + a1 * b4 + a2 * b3 + a3 * b2 + a4 * b1 + a5 * b0;
+    s6 = c6 + a0 * b6 + a1 * b5 + a2 * b4 + a3 * b3 + a4 * b2 + a5 * b1 + a6 * b0;
+    s7 = c7 + a0 * b7 + a1 * b6 + a2 * b5 + a3 * b4 + a4 * b3 + a5 * b2 + a6 * b1 + a7 * b0;
+    s8 = c8 + a0 * b8 + a1 * b7 + a2 * b6 + a3 * b5 + a4 * b4 + a5 * b3 + a6 * b2 + a7 * b1 + a8 * b0;
+    s9 = c9 + a0 * b9 + a1 * b8 + a2 * b7 + a3 * b6 + a4 * b5 + a5 * b4 + a6 * b3 + a7 * b2 + a8 * b1 + a9 * b0;
+    s10 = c10 + a0 * b10 + a1 * b9 + a2 * b8 + a3 * b7 + a4 * b6 + a5 * b5 + a6 * b4 + a7 * b3 + a8 * b2 + a9 * b1 + a10 * b0;
+    s11 = c11 + a0 * b11 + a1 * b10 + a2 * b9 + a3 * b8 + a4 * b7 + a5 * b6 + a6 * b5 + a7 * b4 + a8 * b3 + a9 * b2 + a10 * b1 + a11 * b0;
+    s12 = a1 * b11 + a2 * b10 + a3 * b9 + a4 * b8 + a5 * b7 + a6 * b6 + a7 * b5 + a8 * b4 + a9 * b3 + a10 * b2 + a11 * b1;
+    s13 = a2 * b11 + a3 * b10 + a4 * b9 + a5 * b8 + a6 * b7 + a7 * b6 + a8 * b5 + a9 * b4 + a10 * b3 + a11 * b2;
+    s14 = a3 * b11 + a4 * b10 + a5 * b9 + a6 * b8 + a7 * b7 + a8 * b6 + a9 * b5 + a10 * b4 + a11 * b3;
+    s15 = a4 * b11 + a5 * b10 + a6 * b9 + a7 * b8 + a8 * b7 + a9 * b6 + a10 * b5 + a11 * b4;
+    s16 = a5 * b11 + a6 * b10 + a7 * b9 + a8 * b8 + a9 * b7 + a10 * b6 + a11 * b5;
+    s17 = a6 * b11 + a7 * b10 + a8 * b9 + a9 * b8 + a10 * b7 + a11 * b6;
+    s18 = a7 * b11 + a8 * b10 + a9 * b9 + a10 * b8 + a11 * b7;
+    s19 = a8 * b11 + a9 * b10 + a10 * b9 + a11 * b8;
+    s20 = a9 * b11 + a10 * b10 + a11 * b9;
+    s21 = a10 * b11 + a11 * b10;
+    s22 = a11 * b11;
+    s23 = 0;
+    carry0 = (s0 + (1 << 20)) >> 21;
+    s1 += carry0;
+    s0 -= carry0 << 21;
+    carry2 = (s2 + (1 << 20)) >> 21;
+    s3 += carry2;
+    s2 -= carry2 << 21;
+    carry4 = (s4 + (1 << 20)) >> 21;
+    s5 += carry4;
+    s4 -= carry4 << 21;
+    carry6 = (s6 + (1 << 20)) >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry8 = (s8 + (1 << 20)) >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry10 = (s10 + (1 << 20)) >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+    carry12 = (s12 + (1 << 20)) >> 21;
+    s13 += carry12;
+    s12 -= carry12 << 21;
+    carry14 = (s14 + (1 << 20)) >> 21;
+    s15 += carry14;
+    s14 -= carry14 << 21;
+    carry16 = (s16 + (1 << 20)) >> 21;
+    s17 += carry16;
+    s16 -= carry16 << 21;
+    carry18 = (s18 + (1 << 20)) >> 21;
+    s19 += carry18;
+    s18 -= carry18 << 21;
+    carry20 = (s20 + (1 << 20)) >> 21;
+    s21 += carry20;
+    s20 -= carry20 << 21;
+    carry22 = (s22 + (1 << 20)) >> 21;
+    s23 += carry22;
+    s22 -= carry22 << 21;
+    carry1 = (s1 + (1 << 20)) >> 21;
+    s2 += carry1;
+    s1 -= carry1 << 21;
+    carry3 = (s3 + (1 << 20)) >> 21;
+    s4 += carry3;
+    s3 -= carry3 << 21;
+    carry5 = (s5 + (1 << 20)) >> 21;
+    s6 += carry5;
+    s5 -= carry5 << 21;
+    carry7 = (s7 + (1 << 20)) >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry9 = (s9 + (1 << 20)) >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry11 = (s11 + (1 << 20)) >> 21;
+    s12 += carry11;
+    s11 -= carry11 << 21;
+    carry13 = (s13 + (1 << 20)) >> 21;
+    s14 += carry13;
+    s13 -= carry13 << 21;
+    carry15 = (s15 + (1 << 20)) >> 21;
+    s16 += carry15;
+    s15 -= carry15 << 21;
+    carry17 = (s17 + (1 << 20)) >> 21;
+    s18 += carry17;
+    s17 -= carry17 << 21;
+    carry19 = (s19 + (1 << 20)) >> 21;
+    s20 += carry19;
+    s19 -= carry19 << 21;
+    carry21 = (s21 + (1 << 20)) >> 21;
+    s22 += carry21;
+    s21 -= carry21 << 21;
+    s11 += s23 * 666643;
+    s12 += s23 * 470296;
+    s13 += s23 * 654183;
+    s14 -= s23 * 997805;
+    s15 += s23 * 136657;
+    s16 -= s23 * 683901;
+    s23 = 0;
+    s10 += s22 * 666643;
+    s11 += s22 * 470296;
+    s12 += s22 * 654183;
+    s13 -= s22 * 997805;
+    s14 += s22 * 136657;
+    s15 -= s22 * 683901;
+    s22 = 0;
+    s9 += s21 * 666643;
+    s10 += s21 * 470296;
+    s11 += s21 * 654183;
+    s12 -= s21 * 997805;
+    s13 += s21 * 136657;
+    s14 -= s21 * 683901;
+    s21 = 0;
+    s8 += s20 * 666643;
+    s9 += s20 * 470296;
+    s10 += s20 * 654183;
+    s11 -= s20 * 997805;
+    s12 += s20 * 136657;
+    s13 -= s20 * 683901;
+    s20 = 0;
+    s7 += s19 * 666643;
+    s8 += s19 * 470296;
+    s9 += s19 * 654183;
+    s10 -= s19 * 997805;
+    s11 += s19 * 136657;
+    s12 -= s19 * 683901;
+    s19 = 0;
+    s6 += s18 * 666643;
+    s7 += s18 * 470296;
+    s8 += s18 * 654183;
+    s9 -= s18 * 997805;
+    s10 += s18 * 136657;
+    s11 -= s18 * 683901;
+    s18 = 0;
+    carry6 = (s6 + (1 << 20)) >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry8 = (s8 + (1 << 20)) >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry10 = (s10 + (1 << 20)) >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+    carry12 = (s12 + (1 << 20)) >> 21;
+    s13 += carry12;
+    s12 -= carry12 << 21;
+    carry14 = (s14 + (1 << 20)) >> 21;
+    s15 += carry14;
+    s14 -= carry14 << 21;
+    carry16 = (s16 + (1 << 20)) >> 21;
+    s17 += carry16;
+    s16 -= carry16 << 21;
+    carry7 = (s7 + (1 << 20)) >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry9 = (s9 + (1 << 20)) >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry11 = (s11 + (1 << 20)) >> 21;
+    s12 += carry11;
+    s11 -= carry11 << 21;
+    carry13 = (s13 + (1 << 20)) >> 21;
+    s14 += carry13;
+    s13 -= carry13 << 21;
+    carry15 = (s15 + (1 << 20)) >> 21;
+    s16 += carry15;
+    s15 -= carry15 << 21;
+    s5 += s17 * 666643;
+    s6 += s17 * 470296;
+    s7 += s17 * 654183;
+    s8 -= s17 * 997805;
+    s9 += s17 * 136657;
+    s10 -= s17 * 683901;
+    s17 = 0;
+    s4 += s16 * 666643;
+    s5 += s16 * 470296;
+    s6 += s16 * 654183;
+    s7 -= s16 * 997805;
+    s8 += s16 * 136657;
+    s9 -= s16 * 683901;
+    s16 = 0;
+    s3 += s15 * 666643;
+    s4 += s15 * 470296;
+    s5 += s15 * 654183;
+    s6 -= s15 * 997805;
+    s7 += s15 * 136657;
+    s8 -= s15 * 683901;
+    s15 = 0;
+    s2 += s14 * 666643;
+    s3 += s14 * 470296;
+    s4 += s14 * 654183;
+    s5 -= s14 * 997805;
+    s6 += s14 * 136657;
+    s7 -= s14 * 683901;
+    s14 = 0;
+    s1 += s13 * 666643;
+    s2 += s13 * 470296;
+    s3 += s13 * 654183;
+    s4 -= s13 * 997805;
+    s5 += s13 * 136657;
+    s6 -= s13 * 683901;
+    s13 = 0;
+    s0 += s12 * 666643;
+    s1 += s12 * 470296;
+    s2 += s12 * 654183;
+    s3 -= s12 * 997805;
+    s4 += s12 * 136657;
+    s5 -= s12 * 683901;
+    s12 = 0;
+    carry0 = (s0 + (1 << 20)) >> 21;
+    s1 += carry0;
+    s0 -= carry0 << 21;
+    carry2 = (s2 + (1 << 20)) >> 21;
+    s3 += carry2;
+    s2 -= carry2 << 21;
+    carry4 = (s4 + (1 << 20)) >> 21;
+    s5 += carry4;
+    s4 -= carry4 << 21;
+    carry6 = (s6 + (1 << 20)) >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry8 = (s8 + (1 << 20)) >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry10 = (s10 + (1 << 20)) >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+    carry1 = (s1 + (1 << 20)) >> 21;
+    s2 += carry1;
+    s1 -= carry1 << 21;
+    carry3 = (s3 + (1 << 20)) >> 21;
+    s4 += carry3;
+    s3 -= carry3 << 21;
+    carry5 = (s5 + (1 << 20)) >> 21;
+    s6 += carry5;
+    s5 -= carry5 << 21;
+    carry7 = (s7 + (1 << 20)) >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry9 = (s9 + (1 << 20)) >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry11 = (s11 + (1 << 20)) >> 21;
+    s12 += carry11;
+    s11 -= carry11 << 21;
+    s0 += s12 * 666643;
+    s1 += s12 * 470296;
+    s2 += s12 * 654183;
+    s3 -= s12 * 997805;
+    s4 += s12 * 136657;
+    s5 -= s12 * 683901;
+    s12 = 0;
+    carry0 = s0 >> 21;
+    s1 += carry0;
+    s0 -= carry0 << 21;
+    carry1 = s1 >> 21;
+    s2 += carry1;
+    s1 -= carry1 << 21;
+    carry2 = s2 >> 21;
+    s3 += carry2;
+    s2 -= carry2 << 21;
+    carry3 = s3 >> 21;
+    s4 += carry3;
+    s3 -= carry3 << 21;
+    carry4 = s4 >> 21;
+    s5 += carry4;
+    s4 -= carry4 << 21;
+    carry5 = s5 >> 21;
+    s6 += carry5;
+    s5 -= carry5 << 21;
+    carry6 = s6 >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry7 = s7 >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry8 = s8 >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry9 = s9 >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry10 = s10 >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+    carry11 = s11 >> 21;
+    s12 += carry11;
+    s11 -= carry11 << 21;
+    s0 += s12 * 666643;
+    s1 += s12 * 470296;
+    s2 += s12 * 654183;
+    s3 -= s12 * 997805;
+    s4 += s12 * 136657;
+    s5 -= s12 * 683901;
+    s12 = 0;
+    carry0 = s0 >> 21;
+    s1 += carry0;
+    s0 -= carry0 << 21;
+    carry1 = s1 >> 21;
+    s2 += carry1;
+    s1 -= carry1 << 21;
+    carry2 = s2 >> 21;
+    s3 += carry2;
+    s2 -= carry2 << 21;
+    carry3 = s3 >> 21;
+    s4 += carry3;
+    s3 -= carry3 << 21;
+    carry4 = s4 >> 21;
+    s5 += carry4;
+    s4 -= carry4 << 21;
+    carry5 = s5 >> 21;
+    s6 += carry5;
+    s5 -= carry5 << 21;
+    carry6 = s6 >> 21;
+    s7 += carry6;
+    s6 -= carry6 << 21;
+    carry7 = s7 >> 21;
+    s8 += carry7;
+    s7 -= carry7 << 21;
+    carry8 = s8 >> 21;
+    s9 += carry8;
+    s8 -= carry8 << 21;
+    carry9 = s9 >> 21;
+    s10 += carry9;
+    s9 -= carry9 << 21;
+    carry10 = s10 >> 21;
+    s11 += carry10;
+    s10 -= carry10 << 21;
+    
+    s[0] = (unsigned char) (s0 >> 0);
+    s[1] = (unsigned char) (s0 >> 8);
+    s[2] = (unsigned char) ((s0 >> 16) | (s1 << 5));
+    s[3] = (unsigned char) (s1 >> 3);
+    s[4] = (unsigned char) (s1 >> 11);
+    s[5] = (unsigned char) ((s1 >> 19) | (s2 << 2));
+    s[6] = (unsigned char) (s2 >> 6);
+    s[7] = (unsigned char) ((s2 >> 14) | (s3 << 7));
+    s[8] = (unsigned char) (s3 >> 1);
+    s[9] = (unsigned char) (s3 >> 9);
+    s[10] = (unsigned char) ((s3 >> 17) | (s4 << 4));
+    s[11] = (unsigned char) (s4 >> 4);
+    s[12] = (unsigned char) (s4 >> 12);
+    s[13] = (unsigned char) ((s4 >> 20) | (s5 << 1));
+    s[14] = (unsigned char) (s5 >> 7);
+    s[15] = (unsigned char) ((s5 >> 15) | (s6 << 6));
+    s[16] = (unsigned char) (s6 >> 2);
+    s[17] = (unsigned char) (s6 >> 10);
+    s[18] = (unsigned char) ((s6 >> 18) | (s7 << 3));
+    s[19] = (unsigned char) (s7 >> 5);
+    s[20] = (unsigned char) (s7 >> 13);
+    s[21] = (unsigned char) (s8 >> 0);
+    s[22] = (unsigned char) (s8 >> 8);
+    s[23] = (unsigned char) ((s8 >> 16) | (s9 << 5));
+    s[24] = (unsigned char) (s9 >> 3);
+    s[25] = (unsigned char) (s9 >> 11);
+    s[26] = (unsigned char) ((s9 >> 19) | (s10 << 2));
+    s[27] = (unsigned char) (s10 >> 6);
+    s[28] = (unsigned char) ((s10 >> 14) | (s11 << 7));
+    s[29] = (unsigned char) (s11 >> 1);
+    s[30] = (unsigned char) (s11 >> 9);
+    s[31] = (unsigned char) (s11 >> 17);
+}

lib/ed25519/sc.h

@@ -0,0 +1,12 @@
+#ifndef SC_H
+#define SC_H
+
+/*
+The set of scalars is \Z/l
+where l = 2^252 + 27742317777372353535851937790883648493.
+*/
+
+void sc_reduce(unsigned char *s);
+void sc_muladd(unsigned char *s, const unsigned char *a, const unsigned char *b, const unsigned char *c);
+
+#endif

lib/ed25519/seed.c

@@ -0,0 +1,40 @@
+#include "ed_25519.h"
+
+#ifndef ED25519_NO_SEED
+
+#ifdef _WIN32
+#include <windows.h>
+#include <wincrypt.h>
+#else
+#include <stdio.h>
+#endif
+
+int ed25519_create_seed(unsigned char *seed) {
+#ifdef _WIN32
+    HCRYPTPROV prov;
+
+    if (!CryptAcquireContext(&prov, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT))  {
+        return 1;
+    }
+
+    if (!CryptGenRandom(prov, 32, seed))  {
+        CryptReleaseContext(prov, 0);
+        return 1;
+    }
+
+    CryptReleaseContext(prov, 0);
+#else
+    FILE *f = fopen("/dev/urandom", "rb");
+
+    if (f == NULL) {
+        return 1;
+    }
+
+    fread(seed, 1, 32, f);
+    fclose(f);
+#endif
+
+    return 0;
+}
+
+#endif

lib/ed25519/sha512.c

@@ -0,0 +1,275 @@
+/* LibTomCrypt, modular cryptographic library -- Tom St Denis
+ *
+ * LibTomCrypt is a library that provides various cryptographic
+ * algorithms in a highly modular and flexible manner.
+ *
+ * The library is free for all purposes without any express
+ * guarantee it works.
+ *
+ * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
+ */
+
+#include "fixedint.h"
+#include "sha512.h"
+
+/* the K array */
+static const uint64_t K[80] = {
+    UINT64_C(0x428a2f98d728ae22), UINT64_C(0x7137449123ef65cd), 
+    UINT64_C(0xb5c0fbcfec4d3b2f), UINT64_C(0xe9b5dba58189dbbc),
+    UINT64_C(0x3956c25bf348b538), UINT64_C(0x59f111f1b605d019), 
+    UINT64_C(0x923f82a4af194f9b), UINT64_C(0xab1c5ed5da6d8118),
+    UINT64_C(0xd807aa98a3030242), UINT64_C(0x12835b0145706fbe), 
+    UINT64_C(0x243185be4ee4b28c), UINT64_C(0x550c7dc3d5ffb4e2),
+    UINT64_C(0x72be5d74f27b896f), UINT64_C(0x80deb1fe3b1696b1), 
+    UINT64_C(0x9bdc06a725c71235), UINT64_C(0xc19bf174cf692694),
+    UINT64_C(0xe49b69c19ef14ad2), UINT64_C(0xefbe4786384f25e3), 
+    UINT64_C(0x0fc19dc68b8cd5b5), UINT64_C(0x240ca1cc77ac9c65),
+    UINT64_C(0x2de92c6f592b0275), UINT64_C(0x4a7484aa6ea6e483), 
+    UINT64_C(0x5cb0a9dcbd41fbd4), UINT64_C(0x76f988da831153b5),
+    UINT64_C(0x983e5152ee66dfab), UINT64_C(0xa831c66d2db43210), 
+    UINT64_C(0xb00327c898fb213f), UINT64_C(0xbf597fc7beef0ee4),
+    UINT64_C(0xc6e00bf33da88fc2), UINT64_C(0xd5a79147930aa725), 
+    UINT64_C(0x06ca6351e003826f), UINT64_C(0x142929670a0e6e70),
+    UINT64_C(0x27b70a8546d22ffc), UINT64_C(0x2e1b21385c26c926), 
+    UINT64_C(0x4d2c6dfc5ac42aed), UINT64_C(0x53380d139d95b3df),
+    UINT64_C(0x650a73548baf63de), UINT64_C(0x766a0abb3c77b2a8), 
+    UINT64_C(0x81c2c92e47edaee6), UINT64_C(0x92722c851482353b),
+    UINT64_C(0xa2bfe8a14cf10364), UINT64_C(0xa81a664bbc423001),
+    UINT64_C(0xc24b8b70d0f89791), UINT64_C(0xc76c51a30654be30),
+    UINT64_C(0xd192e819d6ef5218), UINT64_C(0xd69906245565a910), 
+    UINT64_C(0xf40e35855771202a), UINT64_C(0x106aa07032bbd1b8),
+    UINT64_C(0x19a4c116b8d2d0c8), UINT64_C(0x1e376c085141ab53), 
+    UINT64_C(0x2748774cdf8eeb99), UINT64_C(0x34b0bcb5e19b48a8),
+    UINT64_C(0x391c0cb3c5c95a63), UINT64_C(0x4ed8aa4ae3418acb), 
+    UINT64_C(0x5b9cca4f7763e373), UINT64_C(0x682e6ff3d6b2b8a3),
+    UINT64_C(0x748f82ee5defb2fc), UINT64_C(0x78a5636f43172f60), 
+    UINT64_C(0x84c87814a1f0ab72), UINT64_C(0x8cc702081a6439ec),
+    UINT64_C(0x90befffa23631e28), UINT64_C(0xa4506cebde82bde9), 
+    UINT64_C(0xbef9a3f7b2c67915), UINT64_C(0xc67178f2e372532b),
+    UINT64_C(0xca273eceea26619c), UINT64_C(0xd186b8c721c0c207), 
+    UINT64_C(0xeada7dd6cde0eb1e), UINT64_C(0xf57d4f7fee6ed178),
+    UINT64_C(0x06f067aa72176fba), UINT64_C(0x0a637dc5a2c898a6), 
+    UINT64_C(0x113f9804bef90dae), UINT64_C(0x1b710b35131c471b),
+    UINT64_C(0x28db77f523047d84), UINT64_C(0x32caab7b40c72493), 
+    UINT64_C(0x3c9ebe0a15c9bebc), UINT64_C(0x431d67c49c100d4c),
+    UINT64_C(0x4cc5d4becb3e42b6), UINT64_C(0x597f299cfc657e2a), 
+    UINT64_C(0x5fcb6fab3ad6faec), UINT64_C(0x6c44198c4a475817)
+};
+
+/* Various logical functions */
+
+#define ROR64c(x, y) \
+    ( ((((x)&UINT64_C(0xFFFFFFFFFFFFFFFF))>>((uint64_t)(y)&UINT64_C(63))) | \
+      ((x)<<((uint64_t)(64-((y)&UINT64_C(63)))))) & UINT64_C(0xFFFFFFFFFFFFFFFF))
+
+#define STORE64H(x, y)                                                                     \
+   { (y)[0] = (unsigned char)(((x)>>56)&255); (y)[1] = (unsigned char)(((x)>>48)&255);     \
+     (y)[2] = (unsigned char)(((x)>>40)&255); (y)[3] = (unsigned char)(((x)>>32)&255);     \
+     (y)[4] = (unsigned char)(((x)>>24)&255); (y)[5] = (unsigned char)(((x)>>16)&255);     \
+     (y)[6] = (unsigned char)(((x)>>8)&255); (y)[7] = (unsigned char)((x)&255); }
+
+#define LOAD64H(x, y)                                                      \
+   { x = (((uint64_t)((y)[0] & 255))<<56)|(((uint64_t)((y)[1] & 255))<<48) | \
+         (((uint64_t)((y)[2] & 255))<<40)|(((uint64_t)((y)[3] & 255))<<32) | \
+         (((uint64_t)((y)[4] & 255))<<24)|(((uint64_t)((y)[5] & 255))<<16) | \
+         (((uint64_t)((y)[6] & 255))<<8)|(((uint64_t)((y)[7] & 255))); }
+
+
+#define Ch(x,y,z)       (z ^ (x & (y ^ z)))
+#define Maj(x,y,z)      (((x | y) & z) | (x & y)) 
+#define S(x, n)         ROR64c(x, n)
+#define R(x, n)         (((x) &UINT64_C(0xFFFFFFFFFFFFFFFF))>>((uint64_t)n))
+#define Sigma0(x)       (S(x, 28) ^ S(x, 34) ^ S(x, 39))
+#define Sigma1(x)       (S(x, 14) ^ S(x, 18) ^ S(x, 41))
+#define Gamma0(x)       (S(x, 1) ^ S(x, 8) ^ R(x, 7))
+#define Gamma1(x)       (S(x, 19) ^ S(x, 61) ^ R(x, 6))
+#ifndef MIN
+   #define MIN(x, y) ( ((x)<(y))?(x):(y) )
+#endif
+
+/* compress 1024-bits */
+static int sha512_compress(sha512_context *md, unsigned char *buf)
+{
+    uint64_t S[8], W[80], t0, t1;
+    int i;
+
+    /* copy state into S */
+    for (i = 0; i < 8; i++) {
+        S[i] = md->state[i];
+    }
+
+    /* copy the state into 1024-bits into W[0..15] */
+    for (i = 0; i < 16; i++) {
+        LOAD64H(W[i], buf + (8*i));
+    }
+
+    /* fill W[16..79] */
+    for (i = 16; i < 80; i++) {
+        W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) + W[i - 16];
+    }        
+
+/* Compress */
+    #define RND(a,b,c,d,e,f,g,h,i) \
+    t0 = h + Sigma1(e) + Ch(e, f, g) + K[i] + W[i]; \
+    t1 = Sigma0(a) + Maj(a, b, c);\
+    d += t0; \
+    h  = t0 + t1;
+
+    for (i = 0; i < 80; i += 8) {
+       RND(S[0],S[1],S[2],S[3],S[4],S[5],S[6],S[7],i+0);
+       RND(S[7],S[0],S[1],S[2],S[3],S[4],S[5],S[6],i+1);
+       RND(S[6],S[7],S[0],S[1],S[2],S[3],S[4],S[5],i+2);
+       RND(S[5],S[6],S[7],S[0],S[1],S[2],S[3],S[4],i+3);
+       RND(S[4],S[5],S[6],S[7],S[0],S[1],S[2],S[3],i+4);
+       RND(S[3],S[4],S[5],S[6],S[7],S[0],S[1],S[2],i+5);
+       RND(S[2],S[3],S[4],S[5],S[6],S[7],S[0],S[1],i+6);
+       RND(S[1],S[2],S[3],S[4],S[5],S[6],S[7],S[0],i+7);
+   }
+
+   #undef RND
+
+
+
+    /* feedback */
+   for (i = 0; i < 8; i++) {
+        md->state[i] = md->state[i] + S[i];
+    }
+
+    return 0;
+}
+
+
+/**
+   Initialize the hash state
+   @param md   The hash state you wish to initialize
+   @return 0 if successful
+*/
+int sha512_init(sha512_context * md) {
+    if (md == NULL) return 1;
+
+    md->curlen = 0;
+    md->length = 0;
+    md->state[0] = UINT64_C(0x6a09e667f3bcc908);
+    md->state[1] = UINT64_C(0xbb67ae8584caa73b);
+    md->state[2] = UINT64_C(0x3c6ef372fe94f82b);
+    md->state[3] = UINT64_C(0xa54ff53a5f1d36f1);
+    md->state[4] = UINT64_C(0x510e527fade682d1);
+    md->state[5] = UINT64_C(0x9b05688c2b3e6c1f);
+    md->state[6] = UINT64_C(0x1f83d9abfb41bd6b);
+    md->state[7] = UINT64_C(0x5be0cd19137e2179);
+
+    return 0;
+}
+
+/**
+   Process a block of memory though the hash
+   @param md     The hash state
+   @param in     The data to hash
+   @param inlen  The length of the data (octets)
+   @return 0 if successful
+*/
+int sha512_update (sha512_context * md, const unsigned char *in, size_t inlen)               
+{                                                                                           
+    size_t n;
+    size_t i;                                                                        
+    int           err;     
+    if (md == NULL) return 1;  
+    if (in == NULL) return 1;                                                              
+    if (md->curlen > sizeof(md->buf)) {                             
+       return 1;                                                            
+    }                                                                                       
+    while (inlen > 0) {                                                                     
+        if (md->curlen == 0 && inlen >= 128) {                           
+           if ((err = sha512_compress (md, (unsigned char *)in)) != 0) {               
+              return err;                                                                   
+           }                                                                                
+           md->length += 128 * 8;                                        
+           in             += 128;                                                    
+           inlen          -= 128;                                                    
+        } else {                                                                            
+           n = MIN(inlen, (128 - md->curlen));
+
+           for (i = 0; i < n; i++) {
+            md->buf[i + md->curlen] = in[i];
+           }
+
+
+           md->curlen += n;                                                     
+           in             += n;                                                             
+           inlen          -= n;                                                             
+           if (md->curlen == 128) {                                      
+              if ((err = sha512_compress (md, md->buf)) != 0) {            
+                 return err;                                                                
+              }                                                                             
+              md->length += 8*128;                                       
+              md->curlen = 0;                                                   
+           }                                                                                
+       }                                                                                    
+    }                                                                                       
+    return 0;                                                                        
+}
+
+/**
+   Terminate the hash to get the digest
+   @param md  The hash state
+   @param out [out] The destination of the hash (64 bytes)
+   @return 0 if successful
+*/
+   int sha512_final(sha512_context * md, unsigned char *out)
+   {
+    int i;
+
+    if (md == NULL) return 1;
+    if (out == NULL) return 1;
+
+    if (md->curlen >= sizeof(md->buf)) {
+     return 1;
+ }
+
+    /* increase the length of the message */
+ md->length += md->curlen * UINT64_C(8);
+
+    /* append the '1' bit */
+ md->buf[md->curlen++] = (unsigned char)0x80;
+
+    /* if the length is currently above 112 bytes we append zeros
+     * then compress.  Then we can fall back to padding zeros and length
+     * encoding like normal.
+     */
+     if (md->curlen > 112) {
+        while (md->curlen < 128) {
+            md->buf[md->curlen++] = (unsigned char)0;
+        }
+        sha512_compress(md, md->buf);
+        md->curlen = 0;
+    }
+
+    /* pad upto 120 bytes of zeroes 
+     * note: that from 112 to 120 is the 64 MSB of the length.  We assume that you won't hash
+     * > 2^64 bits of data... :-)
+     */
+while (md->curlen < 120) {
+    md->buf[md->curlen++] = (unsigned char)0;
+}
+
+    /* store length */
+STORE64H(md->length, md->buf+120);
+sha512_compress(md, md->buf);
+
+    /* copy output */
+for (i = 0; i < 8; i++) {
+    STORE64H(md->state[i], out+(8*i));
+}
+
+return 0;
+}
+
+int sha512(const unsigned char *message, size_t message_len, unsigned char *out)
+{
+    sha512_context ctx;
+    int ret;
+    if ((ret = sha512_init(&ctx))) return ret;
+    if ((ret = sha512_update(&ctx, message, message_len))) return ret;
+    if ((ret = sha512_final(&ctx, out))) return ret;
+    return 0;
+}

lib/ed25519/sha512.h

@@ -0,0 +1,21 @@
+#ifndef SHA512_H
+#define SHA512_H
+
+#include <stddef.h>
+
+#include "fixedint.h"
+
+/* state */
+typedef struct sha512_context_ {
+    uint64_t  length, state[8];
+    size_t curlen;
+    unsigned char buf[128];
+} sha512_context;
+
+
+int sha512_init(sha512_context * md);
+int sha512_final(sha512_context * md, unsigned char *out);
+int sha512_update(sha512_context * md, const unsigned char *in, size_t inlen);
+int sha512(const unsigned char *message, size_t message_len, unsigned char *out);
+
+#endif

lib/ed25519/sign.c

@@ -0,0 +1,31 @@
+#include "ed_25519.h"
+#include "sha512.h"
+#include "ge.h"
+#include "sc.h"
+
+
+void ed25519_sign(unsigned char *signature, const unsigned char *message, size_t message_len, const unsigned char *public_key, const unsigned char *private_key) {
+    sha512_context hash;
+    unsigned char hram[64];
+    unsigned char r[64];
+    ge_p3 R;
+
+
+    sha512_init(&hash);
+    sha512_update(&hash, private_key + 32, 32);
+    sha512_update(&hash, message, message_len);
+    sha512_final(&hash, r);
+
+    sc_reduce(r);
+    ge_scalarmult_base(&R, r);
+    ge_p3_tobytes(signature, &R);
+
+    sha512_init(&hash);
+    sha512_update(&hash, signature, 32);
+    sha512_update(&hash, public_key, 32);
+    sha512_update(&hash, message, message_len);
+    sha512_final(&hash, hram);
+
+    sc_reduce(hram);
+    sc_muladd(signature + 32, hram, private_key, r);
+}

lib/ed25519/verify.c

@@ -0,0 +1,77 @@
+#include "ed_25519.h"
+#include "sha512.h"
+#include "ge.h"
+#include "sc.h"
+
+static int consttime_equal(const unsigned char *x, const unsigned char *y) {
+    unsigned char r = 0;
+
+    r = x[0] ^ y[0];
+    #define F(i) r |= x[i] ^ y[i]
+    F(1);
+    F(2);
+    F(3);
+    F(4);
+    F(5);
+    F(6);
+    F(7);
+    F(8);
+    F(9);
+    F(10);
+    F(11);
+    F(12);
+    F(13);
+    F(14);
+    F(15);
+    F(16);
+    F(17);
+    F(18);
+    F(19);
+    F(20);
+    F(21);
+    F(22);
+    F(23);
+    F(24);
+    F(25);
+    F(26);
+    F(27);
+    F(28);
+    F(29);
+    F(30);
+    F(31);
+    #undef F
+
+    return !r;
+}
+
+int ed25519_verify(const unsigned char *signature, const unsigned char *message, size_t message_len, const unsigned char *public_key) {
+    unsigned char h[64];
+    unsigned char checker[32];
+    sha512_context hash;
+    ge_p3 A;
+    ge_p2 R;
+
+    if (signature[63] & 224) {
+        return 0;
+    }
+
+    if (ge_frombytes_negate_vartime(&A, public_key) != 0) {
+        return 0;
+    }
+
+    sha512_init(&hash);
+    sha512_update(&hash, signature, 32);
+    sha512_update(&hash, public_key, 32);
+    sha512_update(&hash, message, message_len);
+    sha512_final(&hash, h);
+    
+    sc_reduce(h);
+    ge_double_scalarmult_vartime(&R, h, &A, signature + 32);
+    ge_tobytes(checker, &R);
+
+    if (!consttime_equal(checker, signature)) {
+        return 0;
+    }
+
+    return 1;
+}

license.txt

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2025 Scott Powell
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

platformio.ini

@@ -0,0 +1,94 @@
+; PlatformIO Project Configuration File
+;
+;   Build options: build flags, source filter
+;   Upload options: custom upload port, speed and extra flags
+;   Library options: dependencies, extra library storages
+;   Advanced options: extra scripting
+;
+; Please visit documentation for the other options and examples
+; https://docs.platformio.org/page/projectconf.html
+
+[arduino_base]
+framework = arduino
+monitor_speed = 115200
+lib_deps = 
+  SPI
+  Wire
+  jgromes/RadioLib @ ^6.3.0
+  rweather/Crypto @ ^0.4.0
+build_flags = -w -DNDEBUG -DRADIOLIB_STATIC_ONLY=1
+build_src_filter = +<*.cpp> +<helpers/*.cpp>
+
+[esp32_base]
+extends = arduino_base
+platform = espressif32
+monitor_filters = esp32_exception_decoder
+build_src_filter = ${arduino_base.build_src_filter}
+
+[esp32_S3]
+extends = esp32_base
+platform = espressif32
+board = esp32-s3-devkitc-1
+build_src_filter = ${esp32_base.build_src_filter}
+build_flags =
+  ${esp32_base.build_flags}
+lib_deps =
+  ${esp32_base.lib_deps}
+
+[Heltec_stick_lite]
+extends = esp32_base
+board = heltec_wireless_stick_lite
+
+[Heltec_lora32_v2]
+extends = esp32_base
+board = heltec_wifi_lora_32_V2
+
+; ================
+[Heltec_lora32_v3]
+extends = esp32_base
+board = esp32-s3-devkitc-1
+build_flags =
+  ${esp32_base.build_flags} 
+  -D HELTEC_LORA_V3
+build_src_filter = ${esp32_base.build_src_filter}
+
+[env:Heltec_v3_ping_server]
+extends = Heltec_lora32_v3
+build_src_filter = ${Heltec_lora32_v3.build_src_filter} +<../examples/ping_server/main.cpp>
+
+[env:Heltec_v3_ping_client]
+extends = Heltec_lora32_v3
+build_src_filter = ${Heltec_lora32_v3.build_src_filter} +<../examples/ping_client/main.cpp>
+
+[env:Heltec_v3_repeater]
+extends = Heltec_lora32_v3
+build_flags =
+  ${Heltec_lora32_v3.build_flags} 
+; -D NODE_ID=2
+build_src_filter = ${Heltec_lora32_v3.build_src_filter} +<../examples/simple_repeater/main.cpp>
+
+[env:Heltec_v3_chat_alice]
+extends = Heltec_lora32_v3
+build_flags =
+  ${Heltec_lora32_v3.build_flags} 
+  -D RUN_AS_ALICE=true
+; -D NODE_ID=1
+build_src_filter = ${Heltec_lora32_v3.build_src_filter} +<../examples/simple_secure_chat/main.cpp>
+
+[env:Heltec_v3_chat_bob]
+extends = Heltec_lora32_v3
+build_flags =
+  ${Heltec_lora32_v3.build_flags} 
+  -D RUN_AS_ALICE=false
+; -D NODE_ID=3
+build_src_filter = ${Heltec_lora32_v3.build_src_filter} +<../examples/simple_secure_chat/main.cpp>
+
+[env:Heltec_v3_test_admin]
+extends = Heltec_lora32_v3
+build_flags =
+  ${Heltec_lora32_v3.build_flags} 
+; -D NODE_ID=1
+build_src_filter = ${Heltec_lora32_v3.build_src_filter} +<../examples/test_admin/main.cpp>
+
+; =============
+

src/Destination.cpp

@@ -0,0 +1,29 @@
+#include "Destination.h"
+#include "Utils.h"
+#include <string.h>
+
+namespace mesh {
+
+Destination::Destination(const Identity& identity, const char* name) {
+  uint8_t name_hash[MAX_HASH_SIZE];
+  Utils::sha256(name_hash, MAX_HASH_SIZE, (const uint8_t *)name, strlen(name));
+
+  Utils::sha256(hash, MAX_HASH_SIZE, name_hash, MAX_HASH_SIZE, identity.pub_key, PUB_KEY_SIZE);
+}
+
+Destination::Destination(const char* name) {
+  uint8_t name_hash[MAX_HASH_SIZE];
+  Utils::sha256(name_hash, MAX_HASH_SIZE, (const uint8_t *)name, strlen(name));
+
+  Utils::sha256(hash, MAX_HASH_SIZE, name_hash, MAX_HASH_SIZE);
+}
+
+Destination::Destination() {
+  memset(hash, 0, MAX_HASH_SIZE);
+}
+
+bool Destination::matches(const uint8_t* other_hash) {
+  return memcmp(hash, other_hash, MAX_HASH_SIZE) == 0;
+}
+
+}

src/Destination.h

@@ -0,0 +1,25 @@
+#pragma once
+
+#include <MeshCore.h>
+#include <Identity.h>
+
+namespace mesh {
+
+/**
+ * \brief  Represents an end-point in the mesh, identified by a truncated SHA256 hash. (of DEST_HASH_SIZE)
+ *      The hash is either from just a 'name' (C-string), and these can be thought of as 'broadcast' addresses,
+ *      or can be the hash of name + Identity.public_key
+*/
+class Destination {
+public:
+  uint8_t hash[MAX_HASH_SIZE];
+
+  Destination(const Identity& identity, const char* name);
+  Destination(const char* name);
+  Destination(const uint8_t desthash[]) { memcpy(hash, desthash, MAX_HASH_SIZE); }
+  Destination();
+
+  bool matches(const uint8_t* other_hash);
+};
+
+}

src/Dispatcher.cpp

@@ -0,0 +1,161 @@
+#include "Dispatcher.h"
+
+namespace mesh {
+
+void Dispatcher::begin() {
+  _radio->begin();
+}
+
+float Dispatcher::getAirtimeBudgetFactor() const {
+  return 5.0;   // default, 16.6%  (1/6th)
+}
+
+void Dispatcher::loop() {
+  if (outbound) {  // waiting for outbound send to be completed
+    if (_radio->isSendComplete()) {
+      long t = _ms->getMillis() - outbound_start;
+      total_air_time += t;  // keep track of how much air time we are using
+      //Serial.print("  airtime="); Serial.println(t);
+
+      // will need radio silence up to next_tx_time
+      next_tx_time = futureMillis(t * getAirtimeBudgetFactor());
+
+      _radio->onSendFinished();
+      onPacketSent(outbound);
+      outbound = NULL;
+    } else if (millisHasNowPassed(outbound_expiry)) {
+      MESH_DEBUG_PRINTLN("Dispatcher::loop(): WARNING: outbound packed send timed out!");
+      //Serial.println("  timed out");
+
+      _radio->onSendFinished();
+      releasePacket(outbound);  // return to pool
+      outbound = NULL;
+    } else {
+      return;  // can't do any more radio activity until send is complete or timed out
+    }
+  }
+
+  checkRecv();
+  checkSend();
+}
+
+void Dispatcher::onPacketSent(Packet* packet) {
+  releasePacket(packet);  // default behaviour, return packet to pool
+}
+
+void Dispatcher::checkRecv() {
+  Packet* pkt;
+  {
+    uint8_t raw[MAX_TRANS_UNIT];
+    int len = _radio->recvRaw(raw, MAX_TRANS_UNIT);
+    if (len > 0) {
+      pkt = _mgr->allocNew();
+      if (pkt == NULL) {
+        MESH_DEBUG_PRINTLN("Dispatcher::checkRecv(): WARNING: received data, no unused packets available!");
+      } else {
+        int i = 0;
+#ifdef NODE_ID
+        uint8_t sender_id = raw[i++];
+        if (sender_id == NODE_ID - 1 || sender_id == NODE_ID + 1) {  // simulate that NODE_ID can only hear NODE_ID-1 or NODE_ID+1, eg. 3 can't hear 1
+        } else {
+          _mgr->free(pkt);  // put back into pool
+          return;
+        }
+#endif
+        //Serial.print("LoRa recv: len="); Serial.println(len);
+
+        pkt->header = raw[i++];
+        pkt->path_len = raw[i++];
+
+        if (pkt->path_len > MAX_PATH_SIZE || i + pkt->path_len > len) {
+          MESH_DEBUG_PRINTLN("Dispatcher::checkRecv(): partial or corrupt packet received, len=%d", len);
+          _mgr->free(pkt);  // put back into pool
+          pkt = NULL;
+        } else {
+          memcpy(pkt->path, &raw[i], pkt->path_len); i += pkt->path_len;
+
+          pkt->payload_len = len - i;  // payload is remainder
+          memcpy(pkt->payload, &raw[i], pkt->payload_len);
+        }
+      }
+    } else {
+      pkt = NULL;
+    }
+  }
+  if (pkt) {
+    DispatcherAction action = onRecvPacket(pkt);
+    if (action == ACTION_RELEASE) {
+      _mgr->free(pkt);
+    } else if (action == ACTION_MANUAL_HOLD) {
+      // sub-class is wanting to manually hold Packet instance, and call releasePacket() at appropriate time
+    } else {   // ACTION_RETRANSMIT*
+      uint8_t priority = (action >> 24) - 1;
+      uint32_t _delay = action & 0xFFFFFF;
+
+      _mgr->queueOutbound(pkt, priority, futureMillis(_delay));
+    }
+  }
+}
+
+void Dispatcher::checkSend() {
+  if (_mgr->getOutboundCount() == 0) return;  // nothing waiting to send
+  if (!millisHasNowPassed(next_tx_time)) return;   // still in 'radio silence' phase (from airtime budget setting)
+  if (_radio->isReceiving()) return;  // check if radio is currently mid-receive
+
+  outbound = _mgr->getNextOutbound(_ms->getMillis());
+  if (outbound) {
+    int len = 0;
+    uint8_t raw[MAX_TRANS_UNIT];
+
+#ifdef NODE_ID
+    raw[len++] = NODE_ID;
+#endif
+    raw[len++] = outbound->header;
+    raw[len++] = outbound->path_len;
+    memcpy(&raw[len], outbound->path, outbound->path_len); len += outbound->path_len;
+
+    if (len + outbound->payload_len > MAX_TRANS_UNIT) {
+      MESH_DEBUG_PRINTLN("Dispatcher::checkSend(): FATAL: Invalid packet queued... too long, len=%d", len + outbound->payload_len);
+      _mgr->free(outbound);
+      outbound = NULL;
+    } else {
+      memcpy(&raw[len], outbound->payload, outbound->payload_len); len += outbound->payload_len;
+
+      uint32_t max_airtime = _radio->getEstAirtimeFor(len)*3/2;
+      outbound_start = _ms->getMillis();
+      _radio->startSendRaw(raw, len);
+      outbound_expiry = futureMillis(max_airtime);
+
+      //Serial.print("LoRa send: len="); Serial.print(len);
+    }
+  }
+}
+
+Packet* Dispatcher::obtainNewPacket() {
+  return _mgr->allocNew();  // TODO: zero out all fields
+}
+
+void Dispatcher::releasePacket(Packet* packet) {
+  _mgr->free(packet);
+}
+
+void Dispatcher::sendPacket(Packet* packet, uint8_t priority, uint32_t delay_millis) {
+  if (packet->path_len > MAX_PATH_SIZE || packet->payload_len > MAX_PACKET_PAYLOAD) {
+    MESH_DEBUG_PRINTLN("Dispatcher::sendPacket(): ERROR: invalid packet... path_len=%d, payload_len=%d", (uint32_t) packet->path_len, (uint32_t) packet->payload_len);
+    _mgr->free(packet);
+  } else {
+    _mgr->queueOutbound(packet, priority, futureMillis(delay_millis));
+  }
+}
+
+// Utility function -- handles the case where millis() wraps around back to zero
+//   2's complement arithmetic will handle any unsigned subtraction up to HALF the word size (32-bits in this case)
+bool Dispatcher::millisHasNowPassed(unsigned long timestamp) const {
+  return (long)(_ms->getMillis() - timestamp) > 0;
+}
+
+unsigned long Dispatcher::futureMillis(int millis_from_now) const {
+  return _ms->getMillis() + millis_from_now;
+}
+
+}

src/Dispatcher.h

@@ -0,0 +1,129 @@
+#pragma once
+
+#include <MeshCore.h>
+#include <Identity.h>
+#include <Packet.h>
+#include <Utils.h>
+#include <string.h>
+
+namespace mesh {
+
+/**
+ * \brief  Abstraction of local/volatile clock with Millisecond granularity.
+*/
+class MillisecondClock {
+public:
+  virtual unsigned long getMillis() = 0;
+};
+
+/**
+ * \brief  Abstraction of this device's packet radio.
+*/
+class Radio {
+public:
+  virtual void begin() { }
+
+  /**
+   * \brief  polls for incoming raw packet.
+   * \param  bytes  destination to store incoming raw packet.
+   * \param  sz   maximum packet size allowed.
+   * \returns 0 if no incoming data, otherwise length of complete packet received.
+  */
+  virtual int recvRaw(uint8_t* bytes, int sz) = 0;
+
+  /**
+   * \returns  estimated transmit air-time needed for packet of 'len_bytes', in milliseconds.
+  */
+  virtual uint32_t getEstAirtimeFor(int len_bytes) = 0;
+
+  /**
+   * \brief  starts the raw packet send. (no wait)
+   * \param  bytes   the raw packet data
+   * \param  len  the length in bytes
+  */
+  virtual void startSendRaw(const uint8_t* bytes, int len) = 0;
+
+  /**
+   * \returns true if the previous 'startSendRaw()' completed successfully.
+  */
+  virtual bool isSendComplete() = 0;
+
+  /**
+   * \brief  a hook for doing any necessary clean up after transmit.
+  */
+  virtual void onSendFinished() = 0;
+
+  /**
+   * \returns  true if the radio is currently mid-receive of a packet.
+  */
+  virtual bool isReceiving() { return false; }
+};
+
+/**
+ * \brief  An abstraction for managing instances of Packets (eg. in a static pool),
+ *        and for managing the outbound packet queue.
+*/
+class PacketManager {
+public:
+  virtual Packet* allocNew() = 0;
+  virtual void free(Packet* packet) = 0;
+
+  virtual void queueOutbound(Packet* packet, uint8_t priority, uint32_t scheduled_for) = 0;
+  virtual Packet* getNextOutbound(uint32_t now) = 0;    // by priority
+  virtual int getOutboundCount() const = 0;
+  virtual int getFreeCount() const = 0;
+  virtual Packet* getOutboundByIdx(int i) = 0;
+  virtual Packet* removeOutboundByIdx(int i) = 0;
+};
+
+typedef uint32_t  DispatcherAction;
+
+#define ACTION_RELEASE           (0)
+#define ACTION_MANUAL_HOLD       (1)
+#define ACTION_RETRANSMIT(pri)   (((uint32_t)1 + (pri))<<24)
+#define ACTION_RETRANSMIT_DELAYED(pri, _delay)  ((((uint32_t)1 + (pri))<<24) | (_delay))
+
+/**
+ * \brief  The low-level task that manages detecting incoming Packets, and the queueing
+ *      and scheduling of outbound Packets.
+*/
+class Dispatcher {
+  Packet* outbound;  // current outbound packet
+  unsigned long outbound_expiry, outbound_start, total_air_time;
+  unsigned long next_tx_time;
+
+protected:
+  PacketManager* _mgr;
+  Radio* _radio;
+  MillisecondClock* _ms;
+
+  Dispatcher(Radio& radio, MillisecondClock& ms, PacketManager& mgr)
+    : _radio(&radio), _ms(&ms), _mgr(&mgr)
+  {
+    outbound = NULL; total_air_time = 0; next_tx_time = 0;
+  }
+
+  virtual DispatcherAction onRecvPacket(Packet* pkt) = 0;
+  virtual void onPacketSent(Packet* packet);
+  virtual float getAirtimeBudgetFactor() const;
+
+public:
+  void begin();
+  void loop();
+
+  Packet* obtainNewPacket();
+  void releasePacket(Packet* packet);
+  void sendPacket(Packet* packet, uint8_t priority, uint32_t delay_millis=0);
+
+  unsigned long getTotalAirTime() const { return total_air_time; }  // in milliseconds
+
+  // helper methods
+  bool millisHasNowPassed(unsigned long timestamp) const;
+  unsigned long futureMillis(int millis_from_now) const;
+
+private:
+  void checkRecv();
+  void checkSend();
+};
+
+}

src/Identity.cpp

@@ -0,0 +1,70 @@
+#include "Identity.h"
+#include <string.h>
+#define ED25519_NO_SEED  1
+#include <ed_25519.h>
+
+namespace mesh {
+
+Identity::Identity() {
+  memset(pub_key, 0, sizeof(pub_key));
+}
+
+Identity::Identity(const char* pub_hex) {
+  Utils::fromHex(pub_key, PUB_KEY_SIZE, pub_hex);
+}
+
+bool Identity::verify(const uint8_t* sig, const uint8_t* message, int msg_len) const {
+  return ed25519_verify(sig, message, msg_len, pub_key);
+}
+
+bool Identity::readFrom(Stream& s) {
+  return (s.readBytes(pub_key, PUB_KEY_SIZE) == PUB_KEY_SIZE);
+}
+
+bool Identity::writeTo(Stream& s) const {
+  return (s.write(pub_key, PUB_KEY_SIZE) == PUB_KEY_SIZE);
+}
+
+void Identity::printTo(Stream& s) const {
+  Utils::printHex(s, pub_key, PUB_KEY_SIZE);
+}
+
+LocalIdentity::LocalIdentity() {
+  memset(prv_key, 0, sizeof(prv_key));
+}
+LocalIdentity::LocalIdentity(const char* prv_hex, const char* pub_hex) : Identity(pub_hex) {
+  Utils::fromHex(prv_key, PRV_KEY_SIZE, prv_hex);
+}
+
+LocalIdentity::LocalIdentity(RNG* rng) {
+  uint8_t seed[SEED_SIZE];
+  rng->random(seed, SEED_SIZE);
+  ed25519_create_keypair(pub_key, prv_key, seed);
+}
+
+bool LocalIdentity::readFrom(Stream& s) {
+  bool success = (s.readBytes(pub_key, PUB_KEY_SIZE) == PUB_KEY_SIZE);
+  success = success && (s.readBytes(prv_key, PRV_KEY_SIZE) == PRV_KEY_SIZE);
+  return success;
+}
+
+bool LocalIdentity::writeTo(Stream& s) const {
+  bool success = (s.write(pub_key, PUB_KEY_SIZE) == PUB_KEY_SIZE);
+  success = success && (s.write(prv_key, PRV_KEY_SIZE) == PRV_KEY_SIZE);
+  return success;
+}
+
+void LocalIdentity::printTo(Stream& s) const {
+  s.print("pub_key: "); Utils::printHex(s, pub_key, PUB_KEY_SIZE); s.println();
+  s.print("prv_key: "); Utils::printHex(s, prv_key, PRV_KEY_SIZE); s.println();
+}
+
+void LocalIdentity::sign(uint8_t* sig, const uint8_t* message, int msg_len) const {
+  ed25519_sign(sig, message, msg_len, pub_key, prv_key);
+}
+
+void LocalIdentity::calcSharedSecret(uint8_t* secret, const Identity& other) {
+  ed25519_key_exchange(secret, other.pub_key, prv_key);
+}
+
+}

src/Identity.h

@@ -0,0 +1,75 @@
+#pragma once
+
+#include <Utils.h>
+#include <Stream.h>
+
+namespace mesh {
+
+/**
+ * \brief  An identity in the mesh, with given Ed25519 public key, ie. a party whose signatures can be VERIFIED.
+*/
+class Identity {
+public:
+  uint8_t pub_key[PUB_KEY_SIZE];
+
+  Identity();
+  Identity(const char* pub_hex);
+  Identity(const uint8_t* _pub) { memcpy(pub_key, _pub, PUB_KEY_SIZE); }
+
+  int copyHashTo(uint8_t* dest) const { 
+    memcpy(dest, pub_key, PATH_HASH_SIZE);    // hash is just prefix of pub_key
+    return PATH_HASH_SIZE;
+  }
+  bool isHashMatch(const uint8_t* hash) const {
+    return memcmp(hash, pub_key, PATH_HASH_SIZE) == 0;
+  }
+
+  /**
+   * \brief  Performs Ed25519 signature verification.
+   * \param sig IN - must be SIGNATURE_SIZE buffer.
+   * \param message IN - the original message which was signed.
+   * \param msg_len IN - the length in bytes of message.
+   * \returns true, if signature is valid.
+  */
+  bool verify(const uint8_t* sig, const uint8_t* message, int msg_len) const;
+
+  bool matches(const Identity& other) const { return memcmp(pub_key, other.pub_key, PUB_KEY_SIZE) == 0; }
+  bool matches(const uint8_t* other_pubkey) const { return memcmp(pub_key, other_pubkey, PUB_KEY_SIZE) == 0; }
+
+  bool readFrom(Stream& s);
+  bool writeTo(Stream& s) const;
+  void printTo(Stream& s) const;
+};
+
+/**
+ * \brief  An Identity generated on THIS device, ie. with public/private Ed25519 key pair being on this device.
+*/
+class LocalIdentity : public Identity {
+  uint8_t prv_key[PRV_KEY_SIZE];
+public:
+  LocalIdentity();
+  LocalIdentity(const char* prv_hex, const char* pub_hex);
+  LocalIdentity(RNG* rng);   // create new random
+
+  /**
+   * \brief  Ed25519 digital signature.
+   * \param sig OUT - must be SIGNATURE_SIZE buffer.
+   * \param message IN - the raw message bytes to sign.
+   * \param msg_len IN - the length in bytes of message.
+  */
+  void sign(uint8_t* sig, const uint8_t* message, int msg_len) const;
+
+  /**
+   * \brief  the ECDH key exhange, with Ed25519 public key transposed to Ex25519.
+   * \param  secret OUT - the 'shared secret' (must be PUB_KEY_SIZE bytes)
+   * \param  other IN - the second party in the exchange.
+  */
+  void calcSharedSecret(uint8_t* secret, const Identity& other);
+
+  bool readFrom(Stream& s);
+  bool writeTo(Stream& s) const;
+  void printTo(Stream& s) const;
+};
+
+}
+

src/Mesh.cpp

@@ -0,0 +1,392 @@
+#include "Mesh.h"
+//#include <Arduino.h>
+
+namespace mesh {
+
+void Mesh::begin() {
+  Dispatcher::begin();
+}
+
+void Mesh::loop() {
+  Dispatcher::loop();
+}
+
+bool Mesh::allowPacketForward(mesh::Packet* packet) { 
+  return false;  // by default, Transport NOT enabled
+}
+
+int Mesh::searchPeersByHash(const uint8_t* hash) {
+  return 0;  // not found
+}
+
+int Mesh::searchChannelsByHash(const uint8_t* hash, GroupChannel channels[], int max_matches) {
+  return 0;  // not found
+}
+
+DispatcherAction Mesh::onRecvPacket(Packet* pkt) {
+  if (pkt->getPayloadVer() > PAYLOAD_VER_1) {  // not supported in this firmware version
+    MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): unsupported packet version");
+    return ACTION_RELEASE;
+  }
+
+  if (pkt->isRouteDirect() && pkt->path_len >= PATH_HASH_SIZE) {
+    if (self_id.isHashMatch(pkt->path) && allowPacketForward(pkt)) {
+      // remove our hash from 'path', then re-broadcast
+      pkt->path_len -= PATH_HASH_SIZE;
+      memcpy(pkt->path, &pkt->path[PATH_HASH_SIZE], pkt->path_len);
+      return ACTION_RETRANSMIT(0);   // Routed traffic is HIGHEST priority
+    }
+    return ACTION_RELEASE;   // this node is NOT the next hop (OR this packet has already been forwarded), so discard.
+  }
+
+  DispatcherAction action = ACTION_RELEASE;
+
+  switch (pkt->getPayloadType()) {
+    case PAYLOAD_TYPE_ACK: {
+      int i = 0;
+      uint32_t ack_crc;
+      memcpy(&ack_crc, &pkt->payload[i], 4); i += 4;
+      if (i > pkt->payload_len) {
+        MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete ACK packet");
+      } else {
+        onAckRecv(pkt, ack_crc);
+        action = routeRecvPacket(pkt);
+      }
+      break;
+    }
+    case PAYLOAD_TYPE_PATH:
+    case PAYLOAD_TYPE_REQ:
+    case PAYLOAD_TYPE_RESPONSE:
+    case PAYLOAD_TYPE_TXT_MSG: {
+      int i = 0;
+      uint8_t dest_hash = pkt->payload[i++];
+      uint8_t src_hash = pkt->payload[i++];
+
+      uint8_t* macAndData = &pkt->payload[i];   // MAC + encrypted data 
+      if (i + 2 >= pkt->payload_len) {
+        MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete data packet");
+      } else {
+        if (self_id.isHashMatch(&dest_hash)) {
+          // scan contacts DB, for all matching hashes of 'src_hash' (max 4 matches supported ATM)
+          int num = searchPeersByHash(&src_hash);
+          // for each matching contact, try to decrypt data
+          for (int j = 0; j < num; j++) {
+            uint8_t secret[PUB_KEY_SIZE];
+            getPeerSharedSecret(secret, j);
+
+            // decrypt, checking MAC is valid
+            uint8_t data[MAX_PACKET_PAYLOAD];
+            int len = Utils::MACThenDecrypt(secret, data, macAndData, pkt->payload_len - i);
+            if (len > 0) {  // success!
+              if (pkt->getPayloadType() == PAYLOAD_TYPE_PATH) {
+                int k = 0;
+                uint8_t path_len = data[k++];
+                uint8_t* path = &data[k]; k += path_len;
+                uint8_t extra_type = data[k++];
+                uint8_t* extra = &data[k];
+                uint8_t extra_len = len - k;   // remainder of packet (may be padded with zeroes!)
+                onPeerPathRecv(pkt, j, path, path_len, extra_type, extra, extra_len);
+              } else {
+                onPeerDataRecv(pkt, pkt->getPayloadType(), j, data, len);
+              }
+              break;
+            }
+          }
+        }
+        action = routeRecvPacket(pkt);
+      }
+      break;
+    }
+    case PAYLOAD_TYPE_ANON_REQ: {
+      int i = 0;
+      uint8_t dest_hash = pkt->payload[i++];
+      uint8_t* sender_pub_key = &pkt->payload[i]; i += PUB_KEY_SIZE;
+
+      uint8_t* macAndData = &pkt->payload[i];   // MAC + encrypted data 
+      if (i + 2 >= pkt->payload_len) {
+        MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete data packet");
+      } else {
+        if (self_id.isHashMatch(&dest_hash)) {
+          Identity sender(sender_pub_key);
+
+          uint8_t secret[PUB_KEY_SIZE];
+          self_id.calcSharedSecret(secret, sender);
+
+          // decrypt, checking MAC is valid
+          uint8_t data[MAX_PACKET_PAYLOAD];
+          int len = Utils::MACThenDecrypt(secret, data, macAndData, pkt->payload_len - i);
+          if (len > 0) {  // success!
+            onAnonDataRecv(pkt, pkt->getPayloadType(), sender, data, len);
+          }
+        }
+        action = routeRecvPacket(pkt);
+      }
+      break;
+    }
+    case PAYLOAD_TYPE_GRP_DATA: 
+    case PAYLOAD_TYPE_GRP_TXT: {
+      int i = 0;
+      uint8_t channel_hash = pkt->payload[i++];
+
+      uint8_t* macAndData = &pkt->payload[i];   // MAC + encrypted data 
+      if (i + 2 >= pkt->payload_len) {
+        MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete data packet");
+      } else {
+        // scan channels DB, for all matching hashes of 'channel_hash' (max 2 matches supported ATM)
+        GroupChannel channels[2];
+        int num = searchChannelsByHash(&channel_hash, channels, 2);
+        // for each matching channel, try to decrypt data
+        for (int j = 0; j < num; j++) {
+          // decrypt, checking MAC is valid
+          uint8_t data[MAX_PACKET_PAYLOAD];
+          int len = Utils::MACThenDecrypt(channels[j].secret, data, macAndData, pkt->payload_len - i);
+          if (len > 0) {  // success!
+            onGroupDataRecv(pkt, pkt->getPayloadType(), channels[j], data, len);
+            break;
+          }
+        }
+        action = routeRecvPacket(pkt);
+      }
+      break;
+    }
+    case PAYLOAD_TYPE_ADVERT: {
+      int i = 0;
+      Identity id;
+      memcpy(id.pub_key, &pkt->payload[i], PUB_KEY_SIZE); i += PUB_KEY_SIZE;
+
+      uint32_t timestamp;
+      memcpy(&timestamp, &pkt->payload[i], 4); i += 4;
+      uint8_t* signature = &pkt->payload[i]; i += SIGNATURE_SIZE;
+
+      if (i > pkt->payload_len) {
+        MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): incomplete advertisement packet");
+      } else {
+        uint8_t* app_data = &pkt->payload[i];
+        int app_data_len = pkt->payload_len - i;
+        if (app_data_len > MAX_ADVERT_DATA_SIZE) { app_data_len = MAX_ADVERT_DATA_SIZE; }
+
+        // check that signature is valid
+        bool is_ok;
+        {
+          uint8_t message[PUB_KEY_SIZE + 4 + MAX_ADVERT_DATA_SIZE];
+          int msg_len = 0;
+          memcpy(&message[msg_len], id.pub_key, PUB_KEY_SIZE); msg_len += PUB_KEY_SIZE;
+          memcpy(&message[msg_len], &timestamp, 4); msg_len += 4;
+          memcpy(&message[msg_len], app_data, app_data_len); msg_len += app_data_len;
+
+          is_ok = id.verify(signature, message, msg_len);
+        }
+        if (is_ok) {
+          MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): valid advertisement received!");
+          onAdvertRecv(pkt, id, timestamp, app_data, app_data_len);
+          action = routeRecvPacket(pkt);
+        } else {
+          MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): received advertisement with forged signature!");
+        }
+      }
+      break;
+    }
+    default:
+      MESH_DEBUG_PRINTLN("Mesh::onRecvPacket(): unknown payload type, header: %d", (int) pkt->header);
+      action = routeRecvPacket(pkt);
+      break;
+  }
+  return action;
+}
+
+DispatcherAction Mesh::routeRecvPacket(Packet* packet) {
+  if (packet->isRouteFlood() && packet->path_len + PATH_HASH_SIZE <= MAX_PATH_SIZE && allowPacketForward(packet)) {
+    // append this node's hash to 'path'
+    packet->path_len += self_id.copyHashTo(&packet->path[packet->path_len]);
+
+    // as this propagates outwards, give it lower and lower priority
+    return ACTION_RETRANSMIT(packet->path_len);   // give priority to closer sources, than ones further away
+  }
+  return ACTION_RELEASE;
+}
+
+Packet* Mesh::createAdvert(const LocalIdentity& id, const uint8_t* app_data, size_t app_data_len) {
+  if (app_data_len > MAX_ADVERT_DATA_SIZE) return NULL;
+
+  Packet* packet = obtainNewPacket();
+  if (packet == NULL) {
+    MESH_DEBUG_PRINTLN("Mesh::createAdvert(): error, packet pool empty");
+    return NULL;
+  }
+
+  packet->header = (PAYLOAD_TYPE_ADVERT << PH_TYPE_SHIFT);  // ROUTE_TYPE_* is set later
+  packet->path_len = 0;
+
+  int len = 0;
+  memcpy(&packet->payload[len], id.pub_key, PUB_KEY_SIZE); len += PUB_KEY_SIZE;
+
+  uint32_t emitted_timestamp = _rtc->getCurrentTime();
+  memcpy(&packet->payload[len], &emitted_timestamp, 4); len += 4;
+
+  uint8_t* signature = &packet->payload[len]; len += SIGNATURE_SIZE;  // will fill this in later
+
+  memcpy(&packet->payload[len], app_data, app_data_len); len += app_data_len;
+
+  packet->payload_len = len;
+
+  {
+    uint8_t message[PUB_KEY_SIZE + 4 + MAX_ADVERT_DATA_SIZE];
+    int msg_len = 0;
+    memcpy(&message[msg_len], id.pub_key, PUB_KEY_SIZE); msg_len += PUB_KEY_SIZE;
+    memcpy(&message[msg_len], &emitted_timestamp, 4); msg_len += 4;
+    memcpy(&message[msg_len], app_data, app_data_len); msg_len += app_data_len;
+
+    id.sign(signature, message, msg_len);
+  }
+
+  return packet;
+}
+
+#define MAX_COMBINED_PATH  (MAX_PACKET_PAYLOAD - 2 - CIPHER_BLOCK_SIZE)
+
+Packet* Mesh::createPathReturn(const Identity& dest, const uint8_t* secret, const uint8_t* path, uint8_t path_len, uint8_t extra_type, const uint8_t*extra, size_t extra_len) {
+  if (path_len + extra_len + 5 > MAX_COMBINED_PATH) return NULL;  // too long!!
+
+  Packet* packet = obtainNewPacket();
+  if (packet == NULL) {
+    MESH_DEBUG_PRINTLN("Mesh::createPathReturn(): error, packet pool empty");
+    return NULL;
+  }
+  packet->header = (PAYLOAD_TYPE_PATH << PH_TYPE_SHIFT);  // ROUTE_TYPE_* set later
+  packet->path_len = 0;
+
+  int len = 0;
+  len += dest.copyHashTo(&packet->payload[len]);  // dest hash
+  len += self_id.copyHashTo(&packet->payload[len]);  // src hash
+
+  {
+    int data_len = 0;
+    uint8_t data[MAX_PACKET_PAYLOAD];
+
+    data[data_len++] = path_len;
+    memcpy(&data[data_len], path, path_len); data_len += path_len;
+    if (extra_len > 0) {
+      data[data_len++] = extra_type;
+      memcpy(&data[data_len], extra, extra_len); data_len += extra_len;
+    } else {
+      // append a timestamp, or random blob (to make packet_hash unique)
+      data[data_len++] = 0xFF;  // dummy payload type
+      getRNG()->random(&data[data_len], 4); data_len += 4;
+    }
+
+    len += Utils::encryptThenMAC(secret, &packet->payload[len], data, data_len);
+  }
+
+  packet->payload_len = len;
+
+  return packet;
+}
+
+Packet* Mesh::createDatagram(uint8_t type, const Identity& dest, const uint8_t* secret, const uint8_t* data, size_t data_len) {
+  if (type == PAYLOAD_TYPE_ANON_REQ) {
+    if (data_len + 1 + PUB_KEY_SIZE + CIPHER_BLOCK_SIZE-1 > MAX_PACKET_PAYLOAD) return NULL;
+  } else if (type == PAYLOAD_TYPE_TXT_MSG || type == PAYLOAD_TYPE_REQ || type == PAYLOAD_TYPE_RESPONSE) {
+    if (data_len + 2 + CIPHER_BLOCK_SIZE-1 > MAX_PACKET_PAYLOAD) return NULL;
+  } else {
+    return NULL;  // invalid type
+  }
+
+  Packet* packet = obtainNewPacket();
+  if (packet == NULL) {
+    MESH_DEBUG_PRINTLN("Mesh::createDatagram(): error, packet pool empty");
+    return NULL;
+  }
+  packet->header = (type << PH_TYPE_SHIFT);  // ROUTE_TYPE_* set later
+  packet->path_len = 0;
+
+  int len = 0;
+  if (type == PAYLOAD_TYPE_ANON_REQ) {
+    len += dest.copyHashTo(&packet->payload[len]);  // dest hash
+    memcpy(&packet->payload[len], self_id.pub_key, PUB_KEY_SIZE); len += PUB_KEY_SIZE;  // sender pub_key
+  } else {
+    len += dest.copyHashTo(&packet->payload[len]);  // dest hash
+    len += self_id.copyHashTo(&packet->payload[len]);  // src hash
+  }
+  len += Utils::encryptThenMAC(secret, &packet->payload[len], data, data_len);
+
+  packet->payload_len = len;
+
+  return packet;
+}
+
+Packet* Mesh::createGroupDatagram(uint8_t type, const GroupChannel& channel, const uint8_t* data, size_t data_len) {
+  if (!(type == PAYLOAD_TYPE_GRP_TXT || type == PAYLOAD_TYPE_GRP_DATA)) return NULL;   // invalid type
+  if (data_len + 1 + CIPHER_BLOCK_SIZE-1 > MAX_PACKET_PAYLOAD) return NULL; // too long
+
+  Packet* packet = obtainNewPacket();
+  if (packet == NULL) {
+    MESH_DEBUG_PRINTLN("Mesh::createGroupDatagram(): error, packet pool empty");
+    return NULL;
+  }
+  packet->header = (type << PH_TYPE_SHIFT);  // ROUTE_TYPE_* set later
+  packet->path_len = 0;
+
+  int len = 0;
+  memcpy(&packet->payload[len], channel.hash, PATH_HASH_SIZE); len += PATH_HASH_SIZE;
+  len += Utils::encryptThenMAC(channel.secret, &packet->payload[len], data, data_len);
+
+  packet->payload_len = len;
+
+  return packet;
+}
+
+Packet* Mesh::createAck(uint32_t ack_crc) {
+  Packet* packet = obtainNewPacket();
+  if (packet == NULL) {
+    MESH_DEBUG_PRINTLN("Mesh::createAck(): error, packet pool empty");
+    return NULL;
+  }
+  packet->header = (PAYLOAD_TYPE_ACK << PH_TYPE_SHIFT);  // ROUTE_TYPE_* set later
+  packet->path_len = 0;
+
+  memcpy(packet->payload, &ack_crc, 4);
+  packet->payload_len = 4;
+
+  return packet;
+}
+
+void Mesh::sendFlood(Packet* packet, uint32_t delay_millis) {
+  packet->header &= ~PH_ROUTE_MASK;
+  packet->header |= ROUTE_TYPE_FLOOD;
+
+  allowPacketForward(packet);  // mark this packet as already sent in case it is rebroadcast back to us
+
+  uint8_t pri;
+  if (packet->getPayloadType() == PAYLOAD_TYPE_PATH) {
+    pri = 2;
+  } else if (packet->getPayloadType() == PAYLOAD_TYPE_ADVERT) {
+    pri = 3;   // de-prioritie these
+  } else {
+    pri = 1;
+  }
+  sendPacket(packet, pri, delay_millis);
+}
+
+void Mesh::sendDirect(Packet* packet, const uint8_t* path, uint8_t path_len, uint32_t delay_millis) {
+  packet->header &= ~PH_ROUTE_MASK;
+  packet->header |= ROUTE_TYPE_DIRECT;
+
+  memcpy(packet->path, path, packet->path_len = path_len);
+
+  allowPacketForward(packet);  // mark this packet as already sent in case it is rebroadcast back to us
+
+  sendPacket(packet, 0, delay_millis);
+}
+
+void Mesh::sendZeroHop(Packet* packet, uint32_t delay_millis) {
+  packet->header &= ~PH_ROUTE_MASK;
+  packet->header |= ROUTE_TYPE_DIRECT;
+
+  packet->path_len = 0;  // path_len of zero means Zero Hop
+
+  allowPacketForward(packet);  // mark this packet as already sent in case it is rebroadcast back to us
+
+  sendPacket(packet, 0, delay_millis);
+}
+
+}

src/Mesh.h

@@ -0,0 +1,151 @@
+#pragma once
+
+#include <Dispatcher.h>
+
+namespace mesh {
+
+/**
+ * An abstraction of the device's Realtime Clock.
+*/
+class RTCClock {
+public:
+  /**
+   * \returns  the current time. in UNIX epoch seconds.
+  */
+  virtual uint32_t getCurrentTime() = 0;
+
+  /**
+   * \param time  current time in UNIX epoch seconds.
+  */
+  virtual void setCurrentTime(uint32_t time) = 0;
+};
+
+class GroupChannel {
+public:
+  uint8_t hash[PATH_HASH_SIZE];
+  uint8_t secret[PUB_KEY_SIZE];
+};
+
+/**
+ * \brief  The next layer in the basic Dispatcher task, Mesh recognises the particular Payload TYPES,
+ *     and provides virtual methods for sub-classes on handling incoming, and also preparing outbound Packets.
+*/
+class Mesh : public Dispatcher {
+  RTCClock* _rtc;
+  RNG* _rng;
+
+protected:
+  DispatcherAction onRecvPacket(Packet* pkt) override;
+
+  /**
+   * \brief  Decide what to do with received packet, ie. discard, forward, or hold
+   */
+  DispatcherAction routeRecvPacket(Packet* packet);
+
+  /**
+   * \brief  Check whether this packet should be forwarded (re-transmitted) or not.
+   *     Is sub-classes responsibility to make sure given packet is only transmitted ONCE (by this node)
+   */
+  virtual bool allowPacketForward(Packet* packet);
+
+  /**
+   * \brief  Perform search of local DB of peers/contacts.
+   * \returns  Number of peers with matching hash
+   */
+  virtual int searchPeersByHash(const uint8_t* hash);
+
+  /**
+   * \brief  lookup the ECDH shared-secret between this node and peer by idx (calculate if necessary)
+   * \param  dest_secret  destination array to copy the secret (must be PUB_KEY_SIZE bytes)
+   * \param  peer_idx  index of peer, [0..n) where n is what searchPeersByHash() returned
+   */
+  virtual void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) { }
+
+  /**
+   * \brief  A (now decrypted) data packet has been received (by a known peer).
+   *         NOTE: these can be received multiple times (per sender/msg-id), via different routes
+   * \param  type  one of: PAYLOAD_TYPE_TXT_MSG, PAYLOAD_TYPE_REQ, PAYLOAD_TYPE_RESPONSE
+   * \param  sender_idx  index of peer, [0..n) where n is what searchPeersByHash() returned
+  */
+  virtual void onPeerDataRecv(Packet* packet, uint8_t type, int sender_idx, uint8_t* data, size_t len) { }
+
+  /**
+   * \brief  A path TO peer (sender_idx) has been received. (also with optional 'extra' data encoded)
+   *         NOTE: these can be received multiple times (per sender), via differen routes
+   * \param  sender_idx  index of peer, [0..n) where n is what searchPeersByHash() returned
+  */
+  virtual void onPeerPathRecv(Packet* packet, int sender_idx, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) { }
+
+  virtual int searchChannelsByHash(const uint8_t* hash, GroupChannel channels[], int max_matches);
+
+  /**
+   * \brief  A new incoming Advertisement has been received.
+   *         NOTE: these can be received multiple times (per id/timestamp), via different routes
+  */
+  virtual void onAdvertRecv(Packet* packet, const Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len) { }
+
+  /**
+   * \brief  A (now decrypted) data packet has been received.
+   *         NOTE: these can be received multiple times (per sender/contents), via different routes
+   * \param  type  one of: PAYLOAD_TYPE_ANON_REQ
+   * \param  sender  public key provided by sender
+  */
+  virtual void onAnonDataRecv(Packet* packet, uint8_t type, const Identity& sender, uint8_t* data, size_t len) { }
+
+  /**
+   * \brief  A path TO 'sender' has been received. (also with optional 'extra' data encoded)
+   *         NOTE: these can be received multiple times (per sender), via differen routes
+  */
+  virtual void onPathRecv(Packet* packet, Identity& sender, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) { }
+
+  /**
+   * \brief  An encrypted group data packet has been received.
+   *         NOTE: the same payload can be received multiple times, via different routes
+   * \param  type  one of: PAYLOAD_TYPE_GRP_TXT, PAYLOAD_TYPE_GRP_DATA
+   * \param  channel  the matching GroupChannel
+  */
+  virtual void onGroupDataRecv(Packet* packet, uint8_t type, const GroupChannel& channel, uint8_t* data, size_t len) { }
+
+  /**
+   * \brief  A simple ACK packet has been received.
+   *         NOTE: same ACK can be received multiple times, via different routes
+  */
+  virtual void onAckRecv(Packet* packet, uint32_t ack_crc) { }
+
+  Mesh(Radio& radio, MillisecondClock& ms, RNG& rng, RTCClock& rtc, PacketManager& mgr)
+    : Dispatcher(radio, ms, mgr), _rng(&rng), _rtc(&rtc)
+  {
+  }
+
+public:
+  void begin();
+  void loop();
+
+  LocalIdentity self_id;
+
+  RNG* getRNG() const { return _rng; }
+  RTCClock* getRTCClock() const { return _rtc; }
+
+  Packet* createAdvert(const LocalIdentity& id, const uint8_t* app_data=NULL, size_t app_data_len=0);
+  Packet* createDatagram(uint8_t type, const Identity& dest, const uint8_t* secret, const uint8_t* data, size_t len);
+  Packet* createGroupDatagram(uint8_t type, const GroupChannel& channel, const uint8_t* data, size_t data_len);
+  Packet* createAck(uint32_t ack_crc);
+  Packet* createPathReturn(const Identity& dest, const uint8_t* secret, const uint8_t* path, uint8_t path_len, uint8_t extra_type, const uint8_t*extra, size_t extra_len);
+
+  /**
+   * \brief  send a locally-generated Packet with flood routing
+  */
+  void sendFlood(Packet* packet, uint32_t delay_millis=0);
+
+  /**
+   * \brief  send a locally-generated Packet with Direct routing
+  */
+  void sendDirect(Packet* packet, const uint8_t* path, uint8_t path_len, uint32_t delay_millis=0);
+
+  /**
+   * \brief  send a locally-generated Packet to just neigbor nodes (zero hops)
+  */
+  void sendZeroHop(Packet* packet, uint32_t delay_millis=0);
+};
+
+}

src/MeshCore.h

@@ -0,0 +1,46 @@
+#pragma once
+
+#include <stdint.h>
+
+#define MAX_HASH_SIZE        8
+#define PUB_KEY_SIZE        32
+#define PRV_KEY_SIZE        64
+#define SEED_SIZE           32
+#define SIGNATURE_SIZE      64
+#define MAX_ADVERT_DATA_SIZE  32
+#define CIPHER_KEY_SIZE     16
+#define CIPHER_BLOCK_SIZE   16
+
+// V1
+#define CIPHER_MAC_SIZE      2
+#define PATH_HASH_SIZE       1
+
+#define MAX_PACKET_PAYLOAD  184
+#define MAX_PATH_SIZE        64
+#define MAX_TRANS_UNIT      255
+
+#if MESH_DEBUG && ARDUINO
+  #include <Arduino.h>
+  #define MESH_DEBUG_PRINT(...) Serial.printf(__VA_ARGS__)
+  #define MESH_DEBUG_PRINTLN(F, ...) Serial.printf(F "\n", ##__VA_ARGS__)
+#else
+  #define MESH_DEBUG_PRINT(...) {}
+  #define MESH_DEBUG_PRINTLN(...) {}
+#endif
+
+namespace mesh {
+
+#define  BD_STARTUP_NORMAL     0  // getStartupReason() codes
+#define  BD_STARTUP_RX_PACKET  1
+
+class MainBoard {
+public:
+  virtual uint16_t getBattMilliVolts() = 0;
+  virtual const char* getManufacturerName() const = 0;
+  virtual void onBeforeTransmit() { }
+  virtual void onAfterTransmit() { }
+  virtual void reboot() = 0;
+  virtual uint8_t getStartupReason() const = 0;
+};
+
+}

src/MeshTables.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <Mesh.h>
+
+namespace mesh {
+
+/**
+ * An abstraction of the data tables needed to be maintained, for the routing engine.
+*/
+class MeshTables {
+public:
+  virtual bool hasForwarded(const uint8_t* packet_hash) const = 0;
+  virtual void setHasForwarded(const uint8_t* packet_hash) = 0;
+};
+
+}

src/Packet.cpp

@@ -0,0 +1,23 @@
+#include "Packet.h"
+#include <string.h>
+#include <SHA256.h>
+
+namespace mesh {
+
+Packet::Packet() {
+  header = 0;
+  path_len = 0;
+  payload_len = 0;
+}
+
+
+void Packet::calculatePacketHash(uint8_t* hash) const {
+  SHA256 sha;
+  uint8_t t = getPayloadType();
+  sha.update(&t, 1);
+  sha.update(payload, payload_len);
+  sha.finalize(hash, MAX_HASH_SIZE);
+}
+
+
+}

src/Packet.h

@@ -0,0 +1,73 @@
+#pragma once
+
+#include <MeshCore.h>
+
+namespace mesh {
+
+// Packet::header values
+#define PH_ROUTE_MASK     0x03   // 2-bits
+#define PH_TYPE_SHIFT        2
+#define PH_TYPE_MASK      0x0F   // 4-bits
+#define PH_VER_SHIFT         6
+#define PH_VER_MASK       0x03   // 2-bits
+
+#define ROUTE_TYPE_RESERVED1     0x00    // FUTURE
+#define ROUTE_TYPE_FLOOD         0x01    // flood mode, needs 'path' to be built up (max 64 bytes)
+#define ROUTE_TYPE_DIRECT        0x02    // direct route, 'path' is supplied
+#define ROUTE_TYPE_RESERVED2     0x03    // FUTURE
+
+#define PAYLOAD_TYPE_REQ         0x00    // request (prefixed with dest/src hashes, MAC) (enc data: timestamp, blob)
+#define PAYLOAD_TYPE_RESPONSE    0x01    // response to REQ or ANON_REQ (prefixed with dest/src hashes, MAC) (enc data: timestamp, blob)
+#define PAYLOAD_TYPE_TXT_MSG     0x02    // a plain text message (prefixed with dest/src hashes, MAC) (enc data: timestamp, text)
+#define PAYLOAD_TYPE_ACK         0x03    // a simple ack
+#define PAYLOAD_TYPE_ADVERT      0x04    // a node advertising its Identity
+#define PAYLOAD_TYPE_GRP_TXT     0x05    // an (unverified) group text message (prefixed with channel hash, MAC) (enc data: timestamp, "name: msg")
+#define PAYLOAD_TYPE_GRP_DATA    0x06    // an (unverified) group datagram (prefixed with channel hash, MAC) (enc data: timestamp, blob)
+#define PAYLOAD_TYPE_ANON_REQ    0x07    // generic request (prefixed with dest_hash, ephemeral pub_key, MAC) (enc data: ...)
+#define PAYLOAD_TYPE_PATH        0x08    // returned path (prefixed with dest/src hashes, MAC) (enc data: path, extra)
+//...
+#define PAYLOAD_TYPE_RESERVEDM   0x0F    // FUTURE
+
+#define PAYLOAD_VER_1       0x00   // 1-byte src/dest hashes, 2-byte MAC
+#define PAYLOAD_VER_2       0x01   // FUTURE (eg. 2-byte hashes, 4-byte MAC ??)
+#define PAYLOAD_VER_3       0x02   // FUTURE
+#define PAYLOAD_VER_4       0x03   // FUTURE
+
+/**
+ * \brief  The fundamental transmission unit.
+*/
+class Packet {
+public:
+  Packet();
+
+  uint8_t header;
+  uint16_t payload_len, path_len;
+  uint8_t path[MAX_PATH_SIZE];
+  uint8_t payload[MAX_PACKET_PAYLOAD];
+
+  /**
+   * \brief calculate the hash of payload + type
+   * \param  dest_hash   destination to store the hash (must be MAX_HASH_SIZE bytes)
+   */
+  void calculatePacketHash(uint8_t* dest_hash) const;
+
+  /**
+   * \returns  one of ROUTE_ values
+   */
+  uint8_t getRouteType() const { return header & PH_ROUTE_MASK; }
+
+  bool isRouteFlood() const { return getRouteType() == ROUTE_TYPE_FLOOD; }
+  bool isRouteDirect() const { return getRouteType() == ROUTE_TYPE_DIRECT; }
+
+  /**
+   * \returns  one of PAYLOAD_TYPE_ values
+   */
+  uint8_t getPayloadType() const { return (header >> PH_TYPE_SHIFT) & PH_TYPE_MASK; }
+
+  /**
+   * \returns  one of PAYLOAD_VER_ values
+   */
+  uint8_t getPayloadVer() const { return (header >> PH_VER_SHIFT) & PH_VER_MASK; }
+};
+
+}

src/Utils.cpp

@@ -0,0 +1,149 @@
+#include "Utils.h"
+#include <AES.h>
+#include <SHA256.h>
+
+#ifdef ARDUINO
+  #include <Arduino.h>
+#endif
+
+namespace mesh {
+
+uint32_t RNG::nextInt(uint32_t _min, uint32_t _max) {
+  uint32_t num;
+  random((uint8_t *) &num, sizeof(num));
+  return (num % (_max - _min)) + _min;
+}
+
+void Utils::sha256(uint8_t *hash, size_t hash_len, const uint8_t* msg, int msg_len) {
+  SHA256 sha;
+  sha.update(msg, msg_len);
+  sha.finalize(hash, hash_len);
+}
+
+void Utils::sha256(uint8_t *hash, size_t hash_len, const uint8_t* frag1, int frag1_len, const uint8_t* frag2, int frag2_len) {
+  SHA256 sha;
+  sha.update(frag1, frag1_len);
+  sha.update(frag2, frag2_len);
+  sha.finalize(hash, hash_len);
+}
+
+int Utils::decrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
+  AES128 aes;
+  uint8_t* dp = dest;
+  const uint8_t* sp = src;
+
+  aes.setKey(shared_secret, CIPHER_KEY_SIZE);
+  while (sp - src < src_len) {
+    aes.decryptBlock(dp, sp);
+    dp += 16; sp += 16;
+  }
+
+  return sp - src;  // will always be multiple of 16
+}
+
+int Utils::encrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
+  AES128 aes;
+  uint8_t* dp = dest;
+
+  aes.setKey(shared_secret, CIPHER_KEY_SIZE);
+  while (src_len >= 16) {
+    aes.encryptBlock(dp, src);
+    dp += 16; src += 16; src_len -= 16;
+  }
+  if (src_len > 0) {  // remaining partial block
+    uint8_t tmp[16];
+    memset(tmp, 0, 16);
+    memcpy(tmp, src, src_len);
+    aes.encryptBlock(dp, tmp);
+    dp += 16;
+  }
+  return dp - dest;  // will always be multiple of 16
+}
+
+int Utils::encryptThenMAC(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
+  int enc_len = encrypt(shared_secret, dest + CIPHER_MAC_SIZE, src, src_len);
+
+  SHA256 sha;
+  sha.resetHMAC(shared_secret, PUB_KEY_SIZE);
+  sha.update(dest + CIPHER_MAC_SIZE, enc_len);
+  sha.finalizeHMAC(shared_secret, PUB_KEY_SIZE, dest, CIPHER_MAC_SIZE);
+
+  return CIPHER_MAC_SIZE + enc_len;
+}
+
+int Utils::MACThenDecrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len) {
+  if (src_len <= CIPHER_MAC_SIZE) return 0;  // invalid src bytes
+
+  uint8_t hmac[CIPHER_MAC_SIZE];
+  {
+    SHA256 sha;
+    sha.resetHMAC(shared_secret, PUB_KEY_SIZE);
+    sha.update(src + CIPHER_MAC_SIZE, src_len - CIPHER_MAC_SIZE);
+    sha.finalizeHMAC(shared_secret, PUB_KEY_SIZE, hmac, CIPHER_MAC_SIZE);
+  }
+  if (memcmp(hmac, src, CIPHER_MAC_SIZE) == 0) {
+    return decrypt(shared_secret, dest, src + CIPHER_MAC_SIZE, src_len - CIPHER_MAC_SIZE);
+  }
+  return 0; // invalid HMAC
+}
+
+static const char hex_chars[] = "0123456789ABCDEF";
+
+void Utils::toHex(char* dest, const uint8_t* src, size_t len) {
+  while (len > 0) {
+    uint8_t b = *src++;
+    *dest++ = hex_chars[b >> 4];
+    *dest++ = hex_chars[b & 0x0F];
+    len--;
+  }
+  *dest = 0;
+}
+
+void Utils::printHex(Stream& s, const uint8_t* src, size_t len) {
+  while (len > 0) {
+    uint8_t b = *src++;
+    s.print(hex_chars[b >> 4]);
+    s.print(hex_chars[b & 0x0F]);
+    len--;
+  }
+}
+
+static uint8_t hexVal(char c) {
+  if (c >= 'A' && c <= 'F') return c - 'A' + 10;
+  if (c >= 'a' && c <= 'f') return c - 'a' + 10;
+  if (c >= '0' && c <= '9') return c - '0';
+  return 0;
+}
+
+bool Utils::fromHex(uint8_t* dest, int dest_size, const char *src_hex) {
+  int len = strlen(src_hex);
+  if (len != dest_size*2) return false;  // incorrect length
+
+  uint8_t* dp = dest;
+  while (dp - dest < dest_size) {
+    char ch = *src_hex++;
+    char cl = *src_hex++;
+    *dp++ = (hexVal(ch) << 4) | hexVal(cl);
+  }
+  return true;
+}
+
+int Utils::parseTextParts(char* text, const char* parts[], int max_num, char separator) {
+  int num = 0;
+  char* sp = text;
+  while (*sp && num < max_num) {
+    parts[num++] = sp;
+    while (*sp && *sp != separator) sp++;
+    if (*sp) {
+       *sp++ = 0;  // replace the seperator with a null, and skip past it
+    }
+  }
+  // if we hit the maximum parts, make sure LAST entry does NOT have separator 
+  while (*sp && *sp != separator) sp++;
+  if (*sp) {
+    *sp = 0;  // replace the separator with null
+  }
+  return num;
+}
+
+}

src/Utils.h

@@ -0,0 +1,81 @@
+#pragma once
+
+#include <MeshCore.h>
+#include <Stream.h>
+#include <string.h>
+
+namespace mesh {
+
+class RNG {
+public:
+  virtual void random(uint8_t* dest, size_t sz) = 0;
+  uint32_t nextInt(uint32_t _min, uint32_t _max);
+};
+
+class Utils {
+public:
+  /**
+   * \brief  calculates the SHA256 hash of 'msg', storing in 'hash' and truncating the hash to 'hash_len' bytes.
+  */
+  static void sha256(uint8_t *hash, size_t hash_len, const uint8_t* msg, int msg_len);
+
+  /**
+   * \brief  calculates the SHA256 hash of two fragments, 'frag1' and 'frag2' (in that order), storing in 'hash' and truncating.
+  */
+  static void sha256(uint8_t *hash, size_t hash_len, const uint8_t* frag1, int frag1_len, const uint8_t* frag2, int frag2_len);
+
+  /**
+   * \brief  Encrypts the 'src' bytes using AES128 cipher, using 'shared_secret' as key, with key length fixed at CIPHER_KEY_SIZE.
+   *         Final block is padded with zero bytes before encrypt. Result stored in 'dest'.
+   * \returns  The length in bytes put into 'dest'. (rounded up to block size)
+  */
+  static int encrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len);
+
+  /**
+   * \brief  Decrypt the 'src' bytes using AES128 cipher, using 'shared_secret' as key, with key length fixed at CIPHER_KEY_SIZE.
+   *         'src_len' should be multiple of block size, as returned by 'encrypt()'.
+   * \returns  The length in bytes put into 'dest'. (dest may contain trailing zero bytes in final block)
+  */
+  static int decrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len);
+
+  /**
+   * \brief  encrypts bytes in src, then calculates MAC on ciphertext, inserting into leading bytes of 'dest'.
+   * \returns  total length of bytes in 'dest' (MAC + ciphertext)
+  */
+  static int encryptThenMAC(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len);
+
+  /**
+   * \brief  checks the MAC (in leading bytes of 'src'), then if valid, decrypts remaining bytes in src.
+   * \returns  zero if MAC is invalid, otherwise the length of decrypted bytes in 'dest'
+  */
+  static int MACThenDecrypt(const uint8_t* shared_secret, uint8_t* dest, const uint8_t* src, int src_len);
+
+  /**
+   * \brief  converts 'src' bytes with given length to Hex representation, and null terminates.
+  */
+  static void toHex(char* dest, const uint8_t* src, size_t len);
+
+  /**
+   * \brief  converts 'src_hex' hexadecimal string (should be null term) back to raw bytes, storing in 'dest'.
+   * \param dest_size   must be exactly the expected size in bytes.
+   * \returns  true if successful
+  */
+  static bool fromHex(uint8_t* dest, int dest_size, const char *src_hex);
+
+  /**
+   * \brief  Prints the hexadecimal representation of 'src' bytes of given length, to Stream 's'.
+  */
+  static void printHex(Stream& s, const uint8_t* src, size_t len);
+
+  /**
+   * \brief  parse 'text' into parts separated by 'separator' char.
+   * \param  text  the text to parse (note is MODIFIED!)
+   * \param  parts  destination array to store pointers to starts of parse parts
+   * \param  max_num  max elements to store in 'parts' array
+   * \param  separator  the separator character
+   * \returns  the number of parts parsed (in 'parts')
+   */
+  static int parseTextParts(char* text, const char* parts[], int max_num, char separator=',');
+};
+
+}

src/helpers/ArduinoHelpers.h

@@ -0,0 +1,27 @@
+#pragma once
+
+#include <Mesh.h>
+#include <Arduino.h>
+
+class VolatileRTCClock : public mesh::RTCClock {
+  long millis_offset;
+public:
+  VolatileRTCClock() { millis_offset = 1715770351; } // 15 May 2024, 8:50pm
+  uint32_t getCurrentTime() override { return (millis()/1000 + millis_offset); }
+  void setCurrentTime(uint32_t time) override { millis_offset = time - millis()/1000; }
+};
+
+class ArduinoMillis : public mesh::MillisecondClock {
+public:
+  unsigned long getMillis() override { return millis(); }
+};
+
+class StdRNG : public mesh::RNG {
+public:
+  void begin(long seed) { randomSeed(seed); }
+  void random(uint8_t* dest, size_t sz) override {
+    for (int i = 0; i < sz; i++) {
+      dest[i] = (::random(0, 256) & 0xFF);
+    }
+  }
+};

src/helpers/CustomSX1262.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <RadioLib.h>
+
+#define SX126X_IRQ_HEADER_VALID                     0b0000010000  //  4     4     valid LoRa header received
+
+class CustomSX1262 : public SX1262 {
+  public:
+    CustomSX1262(Module *mod) : SX1262(mod) { }
+
+    bool isReceiving() {
+      uint16_t irq = getIrqStatus();
+      bool hasPreamble = (irq & SX126X_IRQ_HEADER_VALID);
+      return hasPreamble;
+    }
+};

src/helpers/CustomSX1262Wrapper.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "CustomSX1262.h"
+#include "RadioLibWrappers.h"
+
+class CustomSX1262Wrapper : public RadioLibWrapper {
+public:
+  CustomSX1262Wrapper(CustomSX1262& radio, mesh::MainBoard& board) : RadioLibWrapper(radio, board) { }
+  bool isReceiving() override { return ((CustomSX1262 *)_radio)->isReceiving(); }
+  float getLastRSSI() const override { return ((CustomSX1262 *)_radio)->getRSSI(); }
+  float getLastSNR() const override { return ((CustomSX1262 *)_radio)->getSNR(); }
+};

src/helpers/CustomSX1268.h

@@ -0,0 +1,16 @@
+#pragma once
+
+#include <RadioLib.h>
+
+#define SX126X_IRQ_HEADER_VALID                     0b0000010000  //  4     4     valid LoRa header received
+
+class CustomSX1268 : public SX1268 {
+  public:
+    CustomSX1268(Module *mod) : SX1268(mod) { }
+
+    bool isReceiving() {
+      uint16_t irq = getIrqStatus();
+      bool hasPreamble = (irq & SX126X_IRQ_HEADER_VALID);
+      return hasPreamble;
+    }
+};

src/helpers/CustomSX1268Wrapper.h

@@ -0,0 +1,12 @@
+#pragma once
+
+#include "CustomSX1268.h"
+#include "RadioLibWrappers.h"
+
+class CustomSX1268Wrapper : public RadioLibWrapper {
+public:
+  CustomSX1268Wrapper(CustomSX1268& radio, mesh::MainBoard& board) : RadioLibWrapper(radio, board) { }
+  bool isReceiving() override { return ((CustomSX1268 *)_radio)->isReceiving(); }
+  float getLastRSSI() const override { return ((CustomSX1268 *)_radio)->getRSSI(); }
+  float getLastSNR() const override { return ((CustomSX1268 *)_radio)->getSNR(); }
+};

src/helpers/ESP32Board.h

@@ -0,0 +1,48 @@
+#pragma once
+
+#include <MeshCore.h>
+#include <Arduino.h>
+
+#if defined(ESP_PLATFORM)
+
+#include <rom/rtc.h>
+#include <sys/time.h>
+
+class ESP32Board : public mesh::MainBoard {  // abstract class
+public:
+  void begin() {
+    // for future use, sub-classes SHOULD call this from their begin()
+  }
+
+  void reboot() override {
+    esp_restart();
+  }
+};
+
+class ESP32RTCClock : public mesh::RTCClock {
+public:
+  ESP32RTCClock() { }
+  void begin() {
+    esp_reset_reason_t reason = esp_reset_reason();
+    if (reason == ESP_RST_POWERON) {
+      // start with some date/time in the recent past
+      struct timeval tv;
+      tv.tv_sec = 1715770351;  // 15 May 2024, 8:50pm
+      tv.tv_usec = 0;
+      settimeofday(&tv, NULL);
+    }
+  }
+  uint32_t getCurrentTime() override {
+    time_t _now;
+    time(&_now);
+    return _now;
+  }
+  void setCurrentTime(uint32_t time) override { 
+    struct timeval tv;
+    tv.tv_sec = time;
+    tv.tv_usec = 0;
+    settimeofday(&tv, NULL);
+  }
+};
+
+#endif

src/helpers/HeltecV3Board.h

@@ -0,0 +1,91 @@
+#pragma once
+
+#include "ESP32Board.h"
+#include <Arduino.h>
+
+// LoRa radio module pins for Heltec V3
+#define  P_LORA_DIO_1   14
+#define  P_LORA_NSS      8
+#define  P_LORA_RESET   RADIOLIB_NC
+#define  P_LORA_BUSY    13
+#define  P_LORA_SCLK     9
+#define  P_LORA_MISO    11
+#define  P_LORA_MOSI    10
+
+// built-ins
+#define  PIN_VBAT_READ    1
+#define  PIN_ADC_CTRL    37
+#define  PIN_ADC_CTRL_ACTIVE    LOW
+#define  PIN_ADC_CTRL_INACTIVE  HIGH
+#define  PIN_LED_BUILTIN 35
+
+#include <driver/rtc_io.h>
+
+class HeltecV3Board : public ESP32Board {
+  uint8_t startup_reason;
+public:
+  void begin() {
+    startup_reason = BD_STARTUP_NORMAL;
+    ESP32Board::begin();
+
+    esp_reset_reason_t reason = esp_reset_reason();
+    if (reason == ESP_RST_DEEPSLEEP) {
+      long wakeup_source = esp_sleep_get_ext1_wakeup_status();
+      if (wakeup_source & (1 << P_LORA_DIO_1)) {  // received a LoRa packet (while in deep sleep)
+        startup_reason = BD_STARTUP_RX_PACKET;
+      }
+
+      rtc_gpio_hold_dis((gpio_num_t)P_LORA_NSS);
+      rtc_gpio_deinit((gpio_num_t)P_LORA_DIO_1);
+    }
+
+    // battery read support
+    pinMode(PIN_VBAT_READ, INPUT);
+    adcAttachPin(PIN_VBAT_READ);
+    analogReadResolution(10);
+    pinMode(PIN_ADC_CTRL, OUTPUT);
+  }
+
+  uint8_t getStartupReason() const { return startup_reason; }
+
+  void enterDeepSleep(uint32_t secs, int pin_wake_btn = -1) {
+    esp_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_ON);
+
+    // Make sure the DIO1 and NSS GPIOs are hold on required levels during deep sleep 
+    rtc_gpio_set_direction((gpio_num_t)P_LORA_DIO_1, RTC_GPIO_MODE_INPUT_ONLY);
+    rtc_gpio_pulldown_en((gpio_num_t)P_LORA_DIO_1);
+
+    rtc_gpio_hold_en((gpio_num_t)P_LORA_NSS);
+
+    if (pin_wake_btn < 0) {
+      esp_sleep_enable_ext1_wakeup( (1L << P_LORA_DIO_1), ESP_EXT1_WAKEUP_ANY_HIGH);  // wake up on: recv LoRa packet
+    } else {
+      esp_sleep_enable_ext1_wakeup( (1L << P_LORA_DIO_1) | (1L << pin_wake_btn), ESP_EXT1_WAKEUP_ANY_HIGH);  // wake up on: recv LoRa packet OR wake btn
+    }
+
+    if (secs > 0) {
+      esp_sleep_enable_timer_wakeup(secs * 1000000);
+    }
+
+    // Finally set ESP32 into sleep
+    esp_deep_sleep_start();   // CPU halts here and never returns!
+  }
+
+  uint16_t getBattMilliVolts() override {
+    digitalWrite(PIN_ADC_CTRL, PIN_ADC_CTRL_ACTIVE);
+
+    uint32_t raw = 0;
+    for (int i = 0; i < 8; i++) {
+      raw += analogRead(PIN_VBAT_READ);
+    }
+    raw = raw / 8;
+
+    digitalWrite(PIN_ADC_CTRL, PIN_ADC_CTRL_INACTIVE);
+
+    return (5.2 * (3.3 / 1024.0) * raw) * 1000;
+  }
+
+  const char* getManufacturerName() const override {
+    return "Heltec V3";
+  }
+};

src/helpers/IdentityStore.cpp

@@ -0,0 +1,27 @@
+#include "IdentityStore.h"
+
+bool IdentityStore::load(const char *name, mesh::LocalIdentity& id) {
+  bool loaded = false;
+  char filename[40];
+  sprintf(filename, "%s/%s.id", _dir, name);
+  if (_fs->exists(filename)) {
+    File file = _fs->open(filename);
+    if (file) {
+      loaded = id.readFrom(file);
+      file.close();
+    }
+  }
+  return loaded;
+}
+
+bool IdentityStore::save(const char *name, const mesh::LocalIdentity& id) {
+  char filename[40];
+  sprintf(filename, "%s/%s.id", _dir, name);
+  File file = _fs->open(filename, "w", true);
+  if (file) {
+    id.writeTo(file);
+    file.close();
+    return true;
+  }
+  return false;
+}

src/helpers/IdentityStore.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <FS.h>
+#include <Identity.h>
+
+class IdentityStore {
+  fs::FS* _fs;
+  const char* _dir;
+public:
+  IdentityStore(fs::FS& fs, const char* dir): _fs(&fs), _dir(dir) { }
+
+  void begin() { _fs->mkdir(_dir); }
+  bool load(const char *name, mesh::LocalIdentity& id);
+  bool save(const char *name, const mesh::LocalIdentity& id);
+};

src/helpers/RadioLibWrappers.cpp

@@ -0,0 +1,93 @@
+
+#define RADIOLIB_STATIC_ONLY 1
+#include "RadioLibWrappers.h"
+
+#define STATE_IDLE       0
+#define STATE_RX         1
+#define STATE_TX_WAIT    3
+#define STATE_TX_DONE    4
+#define STATE_INT_READY 16
+
+static volatile uint8_t state = STATE_IDLE;
+
+// this function is called when a complete packet
+// is transmitted by the module
+static 
+#if defined(ESP8266) || defined(ESP32)
+  ICACHE_RAM_ATTR
+#endif
+void setFlag(void) {
+  // we sent a packet, set the flag
+  state |= STATE_INT_READY;
+}
+
+void RadioLibWrapper::begin() {
+  _radio->setPacketReceivedAction(setFlag);  // this is also SentComplete interrupt
+  state = STATE_IDLE;
+
+  if (_board->getStartupReason() == BD_STARTUP_RX_PACKET) {  // received a LoRa packet (while in deep sleep)
+    setFlag(); // LoRa packet is already received
+  }
+}
+
+int RadioLibWrapper::recvRaw(uint8_t* bytes, int sz) {
+  if (state & STATE_INT_READY) {
+    int len = _radio->getPacketLength();
+    if (len > 0) {
+      if (len > sz) { len = sz; }
+      int err = _radio->readData(bytes, len);
+      if (err != RADIOLIB_ERR_NONE) {
+        MESH_DEBUG_PRINTLN("RadioLibWrapper: error: readData()");
+      } else {
+      //  Serial.print("  readData() -> "); Serial.println(len);
+      }
+      n_recv++;
+    }
+    state = STATE_IDLE;   // need another startReceive()
+    return len;
+  }
+
+  if (state != STATE_RX) {
+    int err = _radio->startReceive();
+    if (err != RADIOLIB_ERR_NONE) {
+      MESH_DEBUG_PRINTLN("RadioLibWrapper: error: startReceive()");
+    }
+    state = STATE_RX;
+  }
+  return 0;
+}
+
+uint32_t RadioLibWrapper::getEstAirtimeFor(int len_bytes) {
+  return _radio->getTimeOnAir(len_bytes) / 1000;
+}
+
+void RadioLibWrapper::startSendRaw(const uint8_t* bytes, int len) {
+  state = STATE_TX_WAIT;
+  _board->onBeforeTransmit();
+  int err = _radio->startTransmit((uint8_t *) bytes, len);
+  if (err != RADIOLIB_ERR_NONE) {
+    MESH_DEBUG_PRINTLN("RadioLibWrapper: error: startTransmit()");
+  }
+}
+
+bool RadioLibWrapper::isSendComplete() {
+  if (state & STATE_INT_READY) {
+    state = STATE_IDLE;
+    n_sent++;
+    return true;
+  }
+  return false;
+}
+
+void RadioLibWrapper::onSendFinished() {
+  _radio->finishTransmit();
+  _board->onAfterTransmit();
+  state = STATE_IDLE;
+}
+
+float RadioLibWrapper::getLastRSSI() const {
+  return _radio->getRSSI();
+}
+float RadioLibWrapper::getLastSNR() const {
+  return _radio->getSNR();
+}

src/helpers/RadioLibWrappers.h

@@ -0,0 +1,42 @@
+#pragma once
+
+#include <Mesh.h>
+#include <RadioLib.h>
+
+class RadioLibWrapper : public mesh::Radio {
+protected:
+  PhysicalLayer* _radio;
+  mesh::MainBoard* _board;
+  uint32_t n_recv, n_sent;
+
+public:
+  RadioLibWrapper(PhysicalLayer& radio, mesh::MainBoard& board) : _radio(&radio), _board(&board) { n_recv = n_sent = 0; }
+
+  void begin() override;
+  int recvRaw(uint8_t* bytes, int sz) override;
+  uint32_t getEstAirtimeFor(int len_bytes) override;
+  void startSendRaw(const uint8_t* bytes, int len) override;
+  bool isSendComplete() override;
+  void onSendFinished() override;
+
+  uint32_t getPacketsRecv() const { return n_recv; }
+  uint32_t getPacketsSent() const { return n_sent; }
+  virtual float getLastRSSI() const;
+  virtual float getLastSNR() const;
+};
+
+/**
+ * \brief  an RNG impl using the noise from the LoRa radio as entropy.
+ *         NOTE: this is VERY SLOW!  Use only for things like creating new LocalIdentity
+*/
+class RadioNoiseListener : public mesh::RNG {
+  PhysicalLayer* _radio;
+public:
+  RadioNoiseListener(PhysicalLayer& radio): _radio(&radio) { }
+
+  void random(uint8_t* dest, size_t sz) override {
+    for (int i = 0; i < sz; i++) {
+      dest[i] = _radio->randomByte() ^ (::random(0, 256) & 0xFF);
+    }
+  }
+};

src/helpers/SimpleMeshTables.h

@@ -0,0 +1,56 @@
+#pragma once
+
+#include <MeshTables.h>
+
+#ifdef ESP32
+  #include <FS.h>
+#endif
+
+#define MAX_PACKET_HASHES  64
+
+class SimpleMeshTables : public mesh::MeshTables {
+  uint8_t _fwd_hashes[MAX_PACKET_HASHES*MAX_HASH_SIZE];
+  int _next_fwd_idx;
+
+  int lookupHashIndex(const uint8_t* hash) const {
+    const uint8_t* sp = _fwd_hashes;
+    for (int i = 0; i < MAX_PACKET_HASHES; i++, sp += MAX_HASH_SIZE) {
+      if (memcmp(hash, sp, MAX_HASH_SIZE) == 0) return i;
+    }
+    return -1;
+  }
+
+public:
+  SimpleMeshTables() { 
+    memset(_fwd_hashes, 0, sizeof(_fwd_hashes));
+    _next_fwd_idx = 0;
+  }
+
+#ifdef ESP32
+  void restoreFrom(File f) {
+    f.read(_fwd_hashes, sizeof(_fwd_hashes));
+    f.read((uint8_t *) &_next_fwd_idx, sizeof(_next_fwd_idx));
+  }
+  void saveTo(File f) {
+    f.write(_fwd_hashes, sizeof(_fwd_hashes));
+    f.write((const uint8_t *) &_next_fwd_idx, sizeof(_next_fwd_idx));
+  }
+#endif
+
+  bool hasForwarded(const uint8_t* packet_hash) const override {
+    int i = lookupHashIndex(packet_hash);
+    return i >= 0;
+  }
+
+  void setHasForwarded(const uint8_t* packet_hash) override {
+    int i = lookupHashIndex(packet_hash);
+    if (i >= 0) {
+      // already in table
+    } else {
+      memcpy(&_fwd_hashes[_next_fwd_idx*MAX_HASH_SIZE], packet_hash, MAX_HASH_SIZE);
+
+      _next_fwd_idx = (_next_fwd_idx + 1) % MAX_PACKET_HASHES;  // cyclic table
+    }
+  }
+
+};

src/helpers/SimpleSeenTable.h

@@ -0,0 +1,33 @@
+#pragma once
+
+#include <Packet.h>
+#include <string.h>
+
+#define MAX_PACKET_HASHES  64
+
+class SimpleSeenTable {
+  uint8_t _hashes[MAX_PACKET_HASHES*MAX_HASH_SIZE];
+  int _next_idx;
+
+public:
+  SimpleSeenTable() { 
+    memset(_hashes, 0, sizeof(_hashes));
+    _next_idx = 0;
+  }
+
+  bool hasSeenPacket(const mesh::Packet* packet) {
+    uint8_t hash[MAX_HASH_SIZE];
+    packet->calculatePacketHash(hash);
+
+    const uint8_t* sp = _hashes;
+    for (int i = 0; i < MAX_PACKET_HASHES; i++, sp += MAX_HASH_SIZE) {
+      if (memcmp(hash, sp, MAX_HASH_SIZE) == 0) return true;
+    }
+
+    memcpy(&_hashes[_next_idx*MAX_HASH_SIZE], hash, MAX_HASH_SIZE);
+    _next_idx = (_next_idx + 1) % MAX_PACKET_HASHES;  // cyclic table
+
+    return false;
+  }
+
+};

src/helpers/StaticPoolPacketManager.cpp

@@ -0,0 +1,97 @@
+#include "StaticPoolPacketManager.h"
+
+PacketQueue::PacketQueue(int max_entries) {
+  _table = new mesh::Packet*[max_entries];
+  _pri_table = new uint8_t[max_entries];
+  _schedule_table = new uint32_t[max_entries];
+  _size = max_entries;
+  _num = 0;
+}
+
+mesh::Packet* PacketQueue::get(uint32_t now) {
+  uint8_t min_pri = 0xFF;
+  int best_idx = -1;
+  for (int j = 0; j < _num; j++) {
+    if (_schedule_table[j] > now) continue;   // scheduled for future... ignore for now
+    if (_pri_table[j] < min_pri) {  // select most important priority amongst non-future entries
+      min_pri = _pri_table[j];
+      best_idx = j;
+    }
+  }
+  if (best_idx < 0) return NULL;   // empty, or all items are still in the future
+
+  mesh::Packet* top = _table[best_idx];
+  int i = best_idx;
+  _num--;
+  while (i < _num) {
+    _table[i] = _table[i+1];
+    _pri_table[i] = _pri_table[i+1];
+    _schedule_table[i] = _schedule_table[i+1];
+    i++;
+  }
+  return top;
+}
+
+mesh::Packet* PacketQueue::removeByIdx(int i) {
+  if (i >= _num) return NULL;  // invalid index
+
+  mesh::Packet* item = _table[i];
+  _num--;
+  while (i < _num) {
+    _table[i] = _table[i+1];
+    _pri_table[i] = _pri_table[i+1];
+    _schedule_table[i] = _schedule_table[i+1];
+    i++;
+  }
+  return item;
+}
+
+void PacketQueue::add(mesh::Packet* packet, uint8_t priority, uint32_t scheduled_for) {
+  if (_num == _size) {
+    // TODO: log "FATAL: queue is full!"
+    return;
+  }
+  _table[_num] = packet;
+  _pri_table[_num] = priority;
+  _schedule_table[_num] = scheduled_for;
+  _num++;
+}
+
+StaticPoolPacketManager::StaticPoolPacketManager(int pool_size): unused(pool_size), send_queue(pool_size) {
+  // load up our unusued Packet pool
+  for (int i = 0; i < pool_size; i++) {
+    unused.add(new mesh::Packet(), 0, 0);
+  }
+}
+
+mesh::Packet* StaticPoolPacketManager::allocNew() {
+  return unused.removeByIdx(0);  // just get first one (returns NULL if empty)
+}
+
+void StaticPoolPacketManager::free(mesh::Packet* packet) {
+  unused.add(packet, 0, 0);
+}
+
+void StaticPoolPacketManager::queueOutbound(mesh::Packet* packet, uint8_t priority, uint32_t scheduled_for) {
+  send_queue.add(packet, priority, scheduled_for);
+}
+
+mesh::Packet* StaticPoolPacketManager::getNextOutbound(uint32_t now) {
+  //send_queue.sort();   // sort by scheduled_for/priority first
+  return send_queue.get(now);
+}
+
+int  StaticPoolPacketManager::getOutboundCount() const {
+  return send_queue.count();
+}
+
+int StaticPoolPacketManager::getFreeCount() const {
+  return unused.count();
+}
+
+mesh::Packet* StaticPoolPacketManager::getOutboundByIdx(int i) {
+  return send_queue.itemAt(i);
+}
+mesh::Packet* StaticPoolPacketManager::removeOutboundByIdx(int i) {
+  return send_queue.removeByIdx(i);
+}

src/helpers/StaticPoolPacketManager.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <Dispatcher.h>
+
+class PacketQueue {
+  mesh::Packet** _table;
+  uint8_t* _pri_table;
+  uint32_t* _schedule_table;
+  int _size, _num;
+
+public:
+  PacketQueue(int max_entries);
+  mesh::Packet* get(uint32_t now);
+  void add(mesh::Packet* packet, uint8_t priority, uint32_t scheduled_for);
+  int count() const { return _num; }
+  mesh::Packet* itemAt(int i) const { return _table[i]; }
+  mesh::Packet* removeByIdx(int i);
+};
+
+class StaticPoolPacketManager : public mesh::PacketManager {
+  PacketQueue unused, send_queue;
+
+public:
+  StaticPoolPacketManager(int pool_size);
+
+  mesh::Packet* allocNew() override;
+  void free(mesh::Packet* packet) override;
+  void queueOutbound(mesh::Packet* packet, uint8_t priority, uint32_t scheduled_for) override;
+  mesh::Packet* getNextOutbound(uint32_t now) override;
+  int getOutboundCount() const override;
+  int getFreeCount() const override;
+  mesh::Packet* getOutboundByIdx(int i) override;
+  mesh::Packet* removeOutboundByIdx(int i) override;
+};