diff --git a/steam/authenticator.py b/steam/authenticator.py
new file mode 100644
index 0000000..13f2e86
--- /dev/null
+++ b/steam/authenticator.py
@@ -0,0 +1,86 @@
+import json
+
+from guard import *
+from mobileauth import MobileAuth
+
+class MobileAuthenticator:
+  def __init__(self, username, password, authenticatorCredentials=False):
+    self.username = username
+    self.password = password
+    self.ready    = None
+    self.mobile   = MobileAuth(username, password)
+    self.credentials = authenticatorCredentials or { }
+  
+  def login(self):
+    if self.ready != None:
+      return False
+    
+    if 'secret' in self.credentials.keys():
+      code = generate_twofactor_code(self.credentials.get('secret'))
+      self.mobile.login(twofactor_code=code)
+      return True
+    else:
+      try:
+        self.mobile.login()
+      except EmailCodeRequired:
+        raise AuthenticatorAlreadyActive('Two factor authentication already active')
+      except TwoFactorCodeRequired
+        raise AuthenticatorAlreadyActive('Two factor authentication already active')
+      else:
+        self.ready = False
+        return True
+      
+  def addAuthenticator(self):
+    if self.ready != False:
+      return None
+      
+      
+    data = {
+     'steamid': self.mobile.steamid,
+     'sms_phone_id': 1,
+     'access_token': self.mobile.oauth['oauth_token'],
+     'authenticator_time': get_time_offset(),
+     'authenticator_type': 1,
+     'device_identifier': generate_device_id(self.mobile.steamid)
+    }
+      
+    response = self.mobile.request('https://api.steampowered.com/ITwoFactorService/AddAuthenticator/v1/', data)
+    if response.status_code == 200:
+      responseData = json.loads(response.text)
+      self.credentials = responseData['response']
+      self.credentials['secret'] = self.credentials['uri'].split('?secret=')[1].split('&issuer')[0]
+      return True
+    else:
+      return [False, responseData]
+  
+  def finalizeAuthenticator(self, smsCode=None, tries=1):
+    if not smsCode or self.ready != False:
+      return None
+      
+    timestamp = get_time_offset()
+      
+    data = {
+      'steamid': self.mobile.steamid,
+      'access_token': self.mobile.oauth['oauth_token'],
+      'authenticator_time': timestamp,
+      'authenticator_code': generate_twofactor_code_for_time(self.credentials['secret'], timestamp),
+      'activation_code': smsCode
+    }
+    response = self.mobile.request('https://api.steampowered.com/ITwoFactorService/FinalizeAddAuthenticator/v1/', data)
+    if response.status_code == 200:
+      responseData = json.loads(response.text)
+      if responseData['success']:
+        return True
+      else:
+        if responseData['want_more'] and tries < 30:
+          return self.finalizeAuthenticator(smsCode, tries)
+        else:
+          return False
+    else:
+      return False
+      
+class MobileAuthenticatorException(Exception):
+  pass
+
+class AuthenticatorAlreadyActive(MobileAuthenticatorException)
+  pass
diff --git a/steam/mobileauth.py b/steam/mobileauth.py
new file mode 100644
index 0000000..8ac2b0d
--- /dev/null
+++ b/steam/mobileauth.py
@@ -0,0 +1,173 @@
+# -*- coding: utf-8 -*-
+from time import time
+import sys
+from base64 import b64encode
+import requests
+
+from cryptography.hazmat.primitives.asymmetric.rsa import RSAPublicNumbers
+from cryptography.hazmat.primitives.asymmetric.padding import PKCS1v15
+from steam.core.crypto import backend
+
+from steam.util.web import make_requests_session
+from steam import SteamID
+
+if sys.version_info < (3,):
+    intBase = long
+else:
+    intBase = int
+
+
+class MobileAuth(object):
+    key = None
+    complete = False  #: whether authentication has been completed successfully
+    session = None    #: :class:`requests.Session` (with auth cookies after auth is complete)
+    captcha_gid = -1
+    steamid = None    #: :class:`steam.steamid.SteamID` (after auth is complete)
+    oauth = {}
+    def __init__(self, username, password):
+        self.__dict__.update(locals())
+        self.session = make_requests_session()
+
+    @property
+    def captcha_url(self):
+        if self.captcha_gid == -1:
+            return None
+        else:
+            return "https://store.steampowered.com/login/rendercaptcha/?gid=%s" % self.captcha_gid
+
+    def get_rsa_key(self, username):
+        try:
+            resp = self.session.post('https://steamcommunity.com/mobilelogin/getrsakey/',
+                                    timeout=15,
+                                    data={
+                                        'username': username,
+                                        'donotchache': int(time() * 1000),
+                                        },
+                                    ).json()
+        except requests.exceptions.RequestException as e:
+            raise HTTPError(str(e))
+
+        return resp
+
+    def _load_key(self):
+        if not self.key:
+            resp = self.get_rsa_key(self.username)
+
+            nums = RSAPublicNumbers(intBase(resp['publickey_exp'], 16),
+                                    intBase(resp['publickey_mod'], 16),
+                                    )
+
+            self.key = backend.load_rsa_public_numbers(nums)
+            self.timestamp = resp['timestamp']
+            
+    def request(self, uri, data):
+        if not self.complete:
+            return None
+            
+        headers = {
+            'X-Requested-With': 'com.valvesoftware.android.steam.community',
+            'User-agent':  'Mozilla/5.0 (Linux; U; Android 4.1.1; en-us; Google Nexus 4 - 4.1.1 - API 16 - 768x1280 Build/JRO03S) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30'
+        }
+        
+        try:
+            response = self.session.post(uri, data=data, headers=headers)
+        except requests.exceptions.RequestException as e:
+            raise HTTPError(str(e))
+        else:
+            return response
+
+    def refreshSession(self, oauth_token=None):
+        oauth_token = oauth_token or self.oauth['oauth_token']
+        response = self.request('https://api.steampowered.com/IMobileAuthService/GetWGToken/v0001', {'access_token': oauth_token})
+        try:
+            data = json.loads(response)
+        except Exception, e:
+            raise RefreshSessionFailed(str(e))
+        else:
+            self.oauth['wgtoken'] = data['response']['token']
+            self.oauth['wgtoken_secure'] = data['response']['token_secure']
+            self.session.cookies.set('steamLogin', '%s||%s' % (self.steamid, sself.oauth['wgtoken']), domain=domain, secure=False)
+            self.session.cookies.set('steamLoginSecure', '%s||%s' % (self.steamid, self.oauth['wgtoken_secure']), domain=domain, secure=True)
+
+    def login(self, captcha='', email_code='', twofactor_code='', language='english'):
+        if self.complete:
+            return self.session
+            
+        for domain in ['store.steampowered.com', 'help.steampowered.com', 'steamcommunity.com']:
+            self.session.cookies.set('forceMobile', '1', domain=domain, secure=False)
+            self.session.cookies.set('mobileClientVersion', '0 (2.1.3)', domain=domain, secure=False)
+            self.session.cookies.set('mobileClient', 'android', domain=domain, secure=False)
+            self.session.cookies.set('Steam_Language', 'english', domain=domain, secure=False)
+            self.session.cookies.set('dob', '', domain=domain, secure=False)
+
+        self._load_key()
+
+        data = {
+            'username' : self.username,
+            "password": b64encode(self.key.encrypt(self.password.encode('ascii'), PKCS1v15())),
+            "emailauth": email_code,
+            "emailsteamid": str(self.steamid) if email_code else '',
+            "twofactorcode": twofactor_code,
+            "captchagid": self.captcha_gid,
+            "captcha_text": captcha,
+            "loginfriendlyname": "python-steam webauth",
+            "rsatimestamp": self.timestamp,
+            "remember_login": 'true',
+            "donotcache": int(time() * 100000),
+        }
+        data['oauth_client_id'] = 'DE45CD61'
+        data['oauth_scope'] = 'read_profile write_profile read_client write_client'
+        data['loginfriendlyname'] = '#login_emailauth_friendlyname_mobile'
+
+        try:
+            resp = self.session.post('https://steamcommunity.com/mobilelogin/dologin/', data=data, timeout=15).json()
+        except requests.exceptions.RequestException as e:
+            raise HTTPError(str(e))
+
+        self.captcha_gid = -1
+
+        if resp['success'] and resp['login_complete']:
+            self.complete = True
+            self.password = None
+            self.steamid = SteamID(resp['oauth']['steamid'])
+            self.oauth = resp['oauth']
+            for domain in ['store.steampowered.com', 'help.steampowered.com', 'steamcommunity.com']:
+                self.session.cookies.set('steamLogin', '%s||%s' % (self.steamid, resp['oauth']['wgtoken']), domain=domain, secure=False)
+                self.session.cookies.set('steamLoginSecure', '%s||%s' % (self.steamid, data['oauth']['wgtoken_secure']), domain=domain, secure=True)
+
+            return resp
+        else:
+            if resp.get('captcha_needed', False):
+                self.captcha_gid = resp['captcha_gid']
+
+                raise CaptchaRequired(resp['message'])
+            elif resp.get('emailauth_needed', False):
+                self.steamid = SteamID(resp['emailsteamid'])
+                raise EmailCodeRequired(resp['message'])
+            elif resp.get('requires_twofactor', False):
+                raise TwoFactorCodeRequired(resp['message'])
+            else:
+                raise LoginIncorrect(resp['message'])
+
+        return None
+
+class MobileWebAuthException(Exception):
+    pass
+
+class HTTPError(MobileWebAuthException):
+    pass
+
+class LoginIncorrect(MobileWebAuthException):
+    pass
+
+class CaptchaRequired(MobileWebAuthException):
+    pass
+
+class EmailCodeRequired(MobileWebAuthException):
+    pass
+
+class TwoFactorCodeRequired(MobileWebAuthException):
+    pass
+
+class RefreshSessionFailed(MobileWebAuthException):
+    pass