diff --git a/examples/simple_repeater/MyMesh.cpp b/examples/simple_repeater/MyMesh.cpp
index b66e19522..483def34b 100644
--- a/examples/simple_repeater/MyMesh.cpp
+++ b/examples/simple_repeater/MyMesh.cpp
@@ -625,6 +625,31 @@ void MyMesh::getPeerSharedSecret(uint8_t *dest_secret, int peer_idx) {
   }
 }
 
+uint8_t MyMesh::getPeerFlags(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients())
+    return acl.getClientByIdx(i)->flags;
+  return 0;
+}
+
+uint16_t MyMesh::getPeerNextAeadNonce(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients())
+    return acl.getClientByIdx(i)->nextAeadNonce();
+  return 0;
+}
+
+void MyMesh::onPeerAeadDetected(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients()) {
+    auto c = acl.getClientByIdx(i);
+    if (!(c->flags & CONTACT_FLAG_AEAD)) {
+      c->flags |= CONTACT_FLAG_AEAD;
+      getRNG()->random((uint8_t*)&c->aead_nonce, sizeof(c->aead_nonce));
+    }
+  }
+}
+
 static bool isShare(const mesh::Packet *packet) {
   if (packet->hasTransportCodes()) {
     return packet->transport_codes[0] == 0 && packet->transport_codes[1] == 0;  // codes { 0, 0 } means 'send to nowhere'
@@ -668,11 +693,11 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
       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, secret, packet->path, packet->path_len,
-                                              PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
+                                              PAYLOAD_TYPE_RESPONSE, reply_data, reply_len, client->nextAeadNonce());
         if (path) sendFloodReply(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
       } else {
         mesh::Packet *reply =
-            createDatagram(PAYLOAD_TYPE_RESPONSE, client->id, secret, reply_data, reply_len);
+            createDatagram(PAYLOAD_TYPE_RESPONSE, client->id, secret, reply_data, reply_len, client->nextAeadNonce());
         if (reply) {
           if (client->out_path_len != OUT_PATH_UNKNOWN) { // we have an out_path, so send DIRECT
             sendDirect(reply, client->out_path, client->out_path_len, SERVER_RESPONSE_DELAY);
@@ -733,7 +758,7 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
         memcpy(temp, &timestamp, 4);        // mostly an extra blob to help make packet_hash unique
         temp[4] = (TXT_TYPE_CLI_DATA << 2); // NOTE: legacy was: TXT_TYPE_PLAIN
 
-        auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, secret, temp, 5 + text_len);
+        auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, secret, temp, 5 + text_len, client->nextAeadNonce());
         if (reply) {
           if (client->out_path_len == OUT_PATH_UNKNOWN) {
             sendFloodReply(reply, CLI_REPLY_DELAY_MILLIS, packet->getPathHashSize());
diff --git a/examples/simple_repeater/MyMesh.h b/examples/simple_repeater/MyMesh.h
index 0b2e7491b..d8a6a3801 100644
--- a/examples/simple_repeater/MyMesh.h
+++ b/examples/simple_repeater/MyMesh.h
@@ -171,6 +171,9 @@ protected:
   void onAnonDataRecv(mesh::Packet* packet, const uint8_t* secret, const mesh::Identity& sender, uint8_t* data, size_t len) override;
   int searchPeersByHash(const uint8_t* hash) override;
   void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override;
+  uint8_t getPeerFlags(int peer_idx) override;
+  uint16_t getPeerNextAeadNonce(int peer_idx) override;
+  void onPeerAeadDetected(int peer_idx) override;
   void onAdvertRecv(mesh::Packet* packet, const mesh::Identity& id, uint32_t timestamp, const uint8_t* app_data, size_t app_data_len);
   void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, const uint8_t* secret, uint8_t* data, size_t len) override;
   bool onPeerPathRecv(mesh::Packet* packet, int sender_idx, const uint8_t* secret, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override;
diff --git a/examples/simple_room_server/MyMesh.cpp b/examples/simple_room_server/MyMesh.cpp
index 36978e808..352dc8ae0 100644
--- a/examples/simple_room_server/MyMesh.cpp
+++ b/examples/simple_room_server/MyMesh.cpp
@@ -71,7 +71,7 @@ void MyMesh::pushPostToClient(ClientInfo *client, PostInfo &post) {
   mesh::Utils::sha256((uint8_t *)&client->extra.room.pending_ack, 4, reply_data, len, client->id.pub_key, PUB_KEY_SIZE);
   client->extra.room.push_post_timestamp = post.post_timestamp;
 
-  auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, client->shared_secret, reply_data, len);
+  auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, client->shared_secret, reply_data, len, client->nextAeadNonce());
   if (reply) {
     if (client->out_path_len == OUT_PATH_UNKNOWN) {
       unsigned long delay_millis = 0;
@@ -414,6 +414,31 @@ void MyMesh::getPeerSharedSecret(uint8_t *dest_secret, int peer_idx) {
   }
 }
 
+uint8_t MyMesh::getPeerFlags(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients())
+    return acl.getClientByIdx(i)->flags;
+  return 0;
+}
+
+uint16_t MyMesh::getPeerNextAeadNonce(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients())
+    return acl.getClientByIdx(i)->nextAeadNonce();
+  return 0;
+}
+
+void MyMesh::onPeerAeadDetected(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients()) {
+    auto c = acl.getClientByIdx(i);
+    if (!(c->flags & CONTACT_FLAG_AEAD)) {
+      c->flags |= CONTACT_FLAG_AEAD;
+      getRNG()->random((uint8_t*)&c->aead_nonce, sizeof(c->aead_nonce));
+    }
+  }
+}
+
 void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx, const uint8_t *secret,
                             uint8_t *data, size_t len) {
   int i = matching_peer_indexes[sender_idx];
@@ -507,7 +532,7 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
         // mesh::Utils::sha256((uint8_t *)&expected_ack_crc, 4, temp, 5 + text_len, self_id.pub_key,
         // PUB_KEY_SIZE);
 
-        auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, secret, temp, 5 + text_len);
+        auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, client->id, secret, temp, 5 + text_len, client->nextAeadNonce());
         if (reply) {
           if (client->out_path_len == OUT_PATH_UNKNOWN) {
             sendFloodReply(reply, delay_millis + SERVER_RESPONSE_DELAY, packet->getPathHashSize());
@@ -564,10 +589,10 @@ void MyMesh::onPeerDataRecv(mesh::Packet *packet, uint8_t type, int sender_idx,
           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, secret, packet->path, packet->path_len,
-                                                  PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
+                                                  PAYLOAD_TYPE_RESPONSE, reply_data, reply_len, client->nextAeadNonce());
             if (path) sendFloodReply(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
           } else {
-            mesh::Packet *reply = createDatagram(PAYLOAD_TYPE_RESPONSE, client->id, secret, reply_data, reply_len);
+            mesh::Packet *reply = createDatagram(PAYLOAD_TYPE_RESPONSE, client->id, secret, reply_data, reply_len, client->nextAeadNonce());
             if (reply) {
               if (client->out_path_len != OUT_PATH_UNKNOWN) { // we have an out_path, so send DIRECT
                 sendDirect(reply, client->out_path, client->out_path_len, SERVER_RESPONSE_DELAY);
diff --git a/examples/simple_room_server/MyMesh.h b/examples/simple_room_server/MyMesh.h
index 6bab9dc2d..9844a867b 100644
--- a/examples/simple_room_server/MyMesh.h
+++ b/examples/simple_room_server/MyMesh.h
@@ -160,6 +160,9 @@ protected:
   void onAnonDataRecv(mesh::Packet* packet, const uint8_t* secret, const mesh::Identity& sender, uint8_t* data, size_t len) override;
   int searchPeersByHash(const uint8_t* hash) override ;
   void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override;
+  uint8_t getPeerFlags(int peer_idx) override;
+  uint16_t getPeerNextAeadNonce(int peer_idx) override;
+  void onPeerAeadDetected(int peer_idx) override;
   void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, const uint8_t* secret, uint8_t* data, size_t len) override;
   bool onPeerPathRecv(mesh::Packet* packet, int sender_idx, const uint8_t* secret, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override;
   void onAckRecv(mesh::Packet* packet, uint32_t ack_crc) override;
diff --git a/examples/simple_sensor/SensorMesh.cpp b/examples/simple_sensor/SensorMesh.cpp
index 59c9aa090..867437392 100644
--- a/examples/simple_sensor/SensorMesh.cpp
+++ b/examples/simple_sensor/SensorMesh.cpp
@@ -256,7 +256,7 @@ void SensorMesh::sendAlert(const ClientInfo* c, Trigger* t) {
   mesh::Utils::sha256((uint8_t *)&t->expected_acks[t->attempt], 4, data, 5 + text_len, self_id.pub_key, PUB_KEY_SIZE);
   t->attempt++;
 
-  auto pkt = createDatagram(PAYLOAD_TYPE_TXT_MSG, c->id, c->shared_secret, data, 5 + text_len);
+  auto pkt = createDatagram(PAYLOAD_TYPE_TXT_MSG, c->id, c->shared_secret, data, 5 + text_len, c->nextAeadNonce());
   if (pkt) {
     if (c->out_path_len != OUT_PATH_UNKNOWN) {  // we have an out_path, so send DIRECT
       sendDirect(pkt, c->out_path, c->out_path_len);
@@ -500,6 +500,31 @@ void SensorMesh::getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) {
   }
 }
 
+uint8_t SensorMesh::getPeerFlags(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients())
+    return acl.getClientByIdx(i)->flags;
+  return 0;
+}
+
+uint16_t SensorMesh::getPeerNextAeadNonce(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients())
+    return acl.getClientByIdx(i)->nextAeadNonce();
+  return 0;
+}
+
+void SensorMesh::onPeerAeadDetected(int peer_idx) {
+  int i = matching_peer_indexes[peer_idx];
+  if (i >= 0 && i < acl.getNumClients()) {
+    auto c = acl.getClientByIdx(i);
+    if (!(c->flags & CONTACT_FLAG_AEAD)) {
+      c->flags |= CONTACT_FLAG_AEAD;
+      getRNG()->random((uint8_t*)&c->aead_nonce, sizeof(c->aead_nonce));
+    }
+  }
+}
+
 void SensorMesh::sendAckTo(const ClientInfo& dest, uint32_t ack_hash, uint8_t path_hash_size) {
   if (dest.out_path_len == OUT_PATH_UNKNOWN) {
     mesh::Packet* ack = createAck(ack_hash);
@@ -540,10 +565,10 @@ void SensorMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_i
       if (packet->isRouteFlood()) {
         // let this sender know path TO here, so they can use sendDirect(), and ALSO encode the response
         mesh::Packet* path = createPathReturn(from->id, secret, packet->path, packet->path_len,
-                                              PAYLOAD_TYPE_RESPONSE, reply_data, reply_len);
+                                              PAYLOAD_TYPE_RESPONSE, reply_data, reply_len, from->nextAeadNonce());
         if (path) sendFlood(path, SERVER_RESPONSE_DELAY, packet->getPathHashSize());
       } else {
-        mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, from->id, secret, reply_data, reply_len);
+        mesh::Packet* reply = createDatagram(PAYLOAD_TYPE_RESPONSE, from->id, secret, reply_data, reply_len, from->nextAeadNonce());
         if (reply) {
           if (from->out_path_len != OUT_PATH_UNKNOWN) {  // we have an out_path, so send DIRECT
             sendDirect(reply, from->out_path, from->out_path_len, SERVER_RESPONSE_DELAY);
@@ -570,7 +595,7 @@ void SensorMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_i
           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, secret, packet->path, packet->path_len,
-                                                  PAYLOAD_TYPE_ACK, (uint8_t *) &ack_hash, 4);
+                                                  PAYLOAD_TYPE_ACK, (uint8_t *) &ack_hash, 4, from->nextAeadNonce());
             if (path) sendFlood(path, TXT_ACK_DELAY, packet->getPathHashSize());
           } else {
             sendAckTo(*from, ack_hash, packet->getPathHashSize());
@@ -598,7 +623,7 @@ void SensorMesh::onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_i
           memcpy(temp, &timestamp, 4);   // mostly an extra blob to help make packet_hash unique
           temp[4] = (TXT_TYPE_CLI_DATA << 2);
 
-          auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, from->id, secret, temp, 5 + text_len);
+          auto reply = createDatagram(PAYLOAD_TYPE_TXT_MSG, from->id, secret, temp, 5 + text_len, from->nextAeadNonce());
           if (reply) {
             if (from->out_path_len == OUT_PATH_UNKNOWN) {
               sendFlood(reply, CLI_REPLY_DELAY_MILLIS, packet->getPathHashSize());
diff --git a/examples/simple_sensor/SensorMesh.h b/examples/simple_sensor/SensorMesh.h
index 1d65b8772..80d4612ca 100644
--- a/examples/simple_sensor/SensorMesh.h
+++ b/examples/simple_sensor/SensorMesh.h
@@ -125,6 +125,9 @@ protected:
   void onAnonDataRecv(mesh::Packet* packet, const uint8_t* secret, const mesh::Identity& sender, uint8_t* data, size_t len) override;
   int searchPeersByHash(const uint8_t* hash) override;
   void getPeerSharedSecret(uint8_t* dest_secret, int peer_idx) override;
+  uint8_t getPeerFlags(int peer_idx) override;
+  uint16_t getPeerNextAeadNonce(int peer_idx) override;
+  void onPeerAeadDetected(int peer_idx) override;
   void onPeerDataRecv(mesh::Packet* packet, uint8_t type, int sender_idx, const uint8_t* secret, uint8_t* data, size_t len) override;
   bool onPeerPathRecv(mesh::Packet* packet, int sender_idx, const uint8_t* secret, uint8_t* path, uint8_t path_len, uint8_t extra_type, uint8_t* extra, uint8_t extra_len) override;
   void onControlDataRecv(mesh::Packet* packet) override;
diff --git a/src/helpers/ClientACL.h b/src/helpers/ClientACL.h
index b758f7068..7e65c2ca3 100644
--- a/src/helpers/ClientACL.h
+++ b/src/helpers/ClientACL.h
@@ -15,6 +15,8 @@
 struct ClientInfo {
   mesh::Identity id;
   uint8_t permissions;
+  uint8_t flags;                    // transient — includes CONTACT_FLAG_AEAD
+  mutable uint16_t aead_nonce;      // transient — per-peer nonce counter
   uint8_t out_path_len;
   uint8_t out_path[MAX_PATH_SIZE];
   uint8_t shared_secret[PUB_KEY_SIZE];
@@ -30,6 +32,13 @@ struct ClientInfo {
     } room;
   } extra;
   
+  uint16_t nextAeadNonce() const {
+    if (flags & CONTACT_FLAG_AEAD) {
+      if (++aead_nonce == 0) ++aead_nonce;  // skip 0 (means ECB)
+      return aead_nonce;
+    }
+    return 0;
+  }
   bool isAdmin() const { return (permissions & PERM_ACL_ROLE_MASK) == PERM_ACL_ADMIN; }
 };