5 files changed, 407 insertions, 0 deletions
diff --git a/app/assets/javascripts/srp/src/jqueryRest.js b/app/assets/javascripts/srp/src/jqueryRest.js
new file mode 100644
index 0000000..0c58eb2
--- /dev/null
+++ b/app/assets/javascripts/srp/src/jqueryRest.js
@@ -0,0 +1,103 @@
+srp.remote = (function(){
+  var jqueryRest = (function() {
+
+    // TODO: Do we need to differentiate between PUT and POST?
+    function register(session) {
+      return $.post("/1/users.json", {user: session.signup() });
+    }
+
+    function update(session, token) {
+      return $.ajax({
+        url: "/1/users/" + session.id() + ".json",
+        type: 'PUT',
+        headers: { Authorization: 'Token token="' + token + '"' },
+        data: {user: session.update() }
+      });
+    }
+
+    function handshake(session) {
+      return $.post("/1/sessions.json", session.handshake());
+    }
+
+    function authenticate(session) {
+      return $.ajax({
+        url: "/1/sessions/" + session.login() + ".json",
+        type: 'PUT',
+        data: {client_auth: session.getM()}
+      });
+    }
+
+    return {
+      register: register,
+      update: update,
+      handshake: handshake,
+      authenticate: authenticate
+    };
+  }());
+
+
+  function signup(){
+    jqueryRest.register(srp.session)
+    .done(srp.signedUp)
+    .fail(error)
+  };
+
+  function update(submitEvent){
+    var form = submitEvent.target;
+    var token = form.dataset.token;
+    jqueryRest.update(srp.session, token)
+    .done(srp.updated)
+    .fail(error)
+  };
+
+  function login(){
+    jqueryRest.handshake(srp.session)
+    .done(receiveSalts)
+    .fail(error)
+  };
+
+  function receiveSalts(response){
+    // B = 0 will make the algorithm always succeed
+    // -> refuse such a server answer
+    if(response.B === 0) {
+      srp.error("Server send random number 0 - could not login.");
+    }
+    else if(! response.salt || response.salt === 0) {
+      srp.error("Server failed to send salt - could not login.");
+    }
+    else
+    {
+      srp.session.calculations(response.salt, response.B);
+      jqueryRest.authenticate(srp.session)
+      .done(confirmAuthentication)
+      .fail(error);
+    }
+  };
+
+  // Receive M2 from the server and verify it
+  // If an error occurs, raise it as an alert.
+  function confirmAuthentication(response)
+  {
+    if (srp.session.validate(response.M2))
+      srp.loggedIn();
+    else
+      srp.error("Server key does not match");
+  };
+
+  // The server will send error messages as json alongside
+  // the http error response.
+  function error(xhr, text, thrown)
+  {
+    if (xhr.responseText && xhr.responseText != "")
+      srp.error($.parseJSON(xhr.responseText));
+    else
+      srp.error("Server did not respond.");
+  };
+
+  return {
+    signup: signup,
+    update: update,
+    login: login
+  }
+
+}());
diff --git a/app/assets/javascripts/srp/src/srp.js b/app/assets/javascripts/srp/src/srp.js
new file mode 100644
index 0000000..efd50d2
--- /dev/null
+++ b/app/assets/javascripts/srp/src/srp.js
@@ -0,0 +1,24 @@
+var srp = (function(){
+
+  function signup()
+  {
+    srp.remote.signup();
+  };
+
+  function login()
+  {
+    srp.remote.login();
+  };
+
+  function update(submitEvent)
+  {
+    srp.remote.update(submitEvent);
+  };
+
+  return {
+    signup: signup,
+    update: update,
+    login: login
+  }
+}());
+
diff --git a/app/assets/javascripts/srp/src/srp_account.js b/app/assets/javascripts/srp/src/srp_account.js
new file mode 100644
index 0000000..e949f12
--- /dev/null
+++ b/app/assets/javascripts/srp/src/srp_account.js
@@ -0,0 +1,17 @@
+srp.Account = function(login, password, id) {
+
+  // Returns the user's identity
+  this.login = function() {
+    return login || document.getElementById("srp_username").value;
+  };
+
+  // Returns the password currently typed in
+  this.password = function() {
+    return password || document.getElementById("srp_password").value;
+  };
+
+  // The user's id
+  this.id = function() {
+    return id || document.getElementById("user_param").value;
+  };
+}
diff --git a/app/assets/javascripts/srp/src/srp_calculate.js b/app/assets/javascripts/srp/src/srp_calculate.js
new file mode 100644
index 0000000..e32def8
--- /dev/null
+++ b/app/assets/javascripts/srp/src/srp_calculate.js
@@ -0,0 +1,141 @@
+srp.Calculate = function() {
+
+  // Variables used in the SRP protocol
+  var Nstr = "eeaf0ab9adb38dd69c33f80afa8fc5e86072618775ff3c0b9ea2314c9c256576d674df7496ea81d3383b4813d692c6e0e0d5d8e250b98be48e495c1d6089dad15dc7d7b46154d6b6ce8ef4ad69b15d4982559b297bcf1885c529f566660e57ec68edbc3c05726cc02fd4cbf4976eaa9afd5138fe8376435b9fc61d2fc0eb06e3";
+  var N = new BigInteger(Nstr, 16);
+  var g = new BigInteger("2");
+  var k = new BigInteger("bf66c44a428916cad64aa7c679f3fd897ad4c375e9bbb4cbf2f5de241d618ef0", 16);
+  var rng = new SecureRandom();
+
+  this.A = function(_a) { 
+    a = new BigInteger(_a, 16);
+    return zeroPrefix(g.modPow(a, N).toString(16));
+  };
+
+  // Calculates the X value
+  // x = H(s, H(I:p))
+  this.X = function(login, password, salt) {
+    var salted = salt + this.hash(login + ":" + password)
+    return this.hashHex(salted);
+  };
+
+  this.V = this.A;
+
+  // u = H(A,B)
+  this.U = function(A, B) {
+    return this.hashHex(A + B); 
+  };
+
+  //S = (B - kg^x) ^ (a + ux)
+  this.S = function(_a, _A, _B, _x) {
+    var a = new BigInteger(_a, 16);
+    var x = new BigInteger(_x, 16);
+    var u = new BigInteger(this.U(_A, _B), 16);
+    var B = new BigInteger(_B, 16);
+    
+    var kgx = k.multiply(g.modPow(x, N));  
+    var aux = a.add(u.multiply(x)); 
+    
+    return zeroPrefix(B.subtract(kgx).modPow(aux, N).toString(16)); 
+  }
+
+  this.K = function(_S) {
+    return this.hashHex(_S);
+  }
+
+  this.nXorG = function() {
+    var hashN = this.hashHex(Nstr);
+    var hashG = this.hashHex(g.toString(16));
+    return hexXor(hashN, hashG);
+  };
+
+  this.hashHex = function(hexString) {
+    return SHA256(hex2a(hexString));
+  };
+
+  this.hash = function(string) {
+    return SHA256(utf8Encode(string));
+  };
+
+  this.isInvalidEphemeral = function(a) {
+    return (g.modPow(a, N) == 0);
+  };
+
+  this.randomEphemeral = function() {
+    var a = new BigInteger(32, rng);
+    while(this.isInvalidEphemeral(a))
+    {
+      a = new BigInteger(32, rng);
+    }
+    return zeroPrefix(a.toString(16));
+  };
+  
+  // some 16 byte random number
+  this.randomSalt = function() {
+    var salt = new BigInteger(64, rng);
+    return zeroPrefix(salt.toString(16));
+  }
+
+  // expose zeroPrefix for received values.
+  this.zeroPrefix = zeroPrefix;
+
+  function hex2a(hex) {
+    var str = '';
+    if(hex.length % 2) {
+      hex = "0" + hex;
+    }
+    for (var i = 0; i < hex.length; i += 2)
+      str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
+    return str;
+  }
+
+
+  function zeroPrefix(hex) {
+    if (hex.length % 2) {
+      return "0" + hex;
+    } else {
+      return hex;
+    }
+  }
+    
+
+  function removeLeading0(hex) {
+    if (hex[0] == "0") {
+      return hex.substr(1);
+    } else {
+      return hex;
+    }
+  }
+
+  function hexXor(a, b) {
+    var str = '';
+    for (var i = 0; i < a.length; i += 2) {
+      var xor = parseInt(a.substr(i, 2), 16) ^ parseInt(b.substr(i, 2), 16)
+      xor = xor.toString(16);
+      str += (xor.length == 1) ? ("0" + xor) : xor
+    }
+    return str;
+  }
+  
+  function utf8Encode(string) {
+    string = string.replace(/\r\n/g,"\n");
+    var utftext = "";
+
+    for (var n = 0; n < string.length; n++) {
+      var c = string.charCodeAt(n);
+      if (c < 128) {
+        utftext += String.fromCharCode(c);
+      }
+      else if((c > 127) && (c < 2048)) {
+        utftext += String.fromCharCode((c >> 6) | 192);
+        utftext += String.fromCharCode((c & 63) | 128);
+      }
+      else {
+        utftext += String.fromCharCode((c >> 12) | 224);
+        utftext += String.fromCharCode(((c >> 6) & 63) | 128);
+        utftext += String.fromCharCode((c & 63) | 128);
+      }
+    }
+    return utftext;
+  }
+};
diff --git a/app/assets/javascripts/srp/src/srp_session.js b/app/assets/javascripts/srp/src/srp_session.js
new file mode 100644
index 0000000..88f19d5
--- /dev/null
+++ b/app/assets/javascripts/srp/src/srp_session.js
@@ -0,0 +1,122 @@
+srp.Session = function(account, calculate) {
+
+  // default for injected dependency
+  account = account || new srp.Account();
+  calculate = calculate || new srp.Calculate();
+
+  var a = calculate.randomEphemeral();
+  var A = calculate.A(a);
+  var S = null;
+  var K = null;
+  var M = null;
+  var M2 = null;
+  var authenticated = false;
+
+  // *** Accessor methods ***
+
+  // allows setting the random number A for testing
+
+  this.calculateAndSetA = function(_a) {
+    a = _a;
+    A = calculate.A(_a);
+    return A;
+  };
+
+  this.update = function() {
+    var salt = calculate.randomSalt();
+    var x = calculate.X(account.login(), account.password(), salt);
+    return {
+      login: account.login(),
+      password_salt: salt,
+      password_verifier: calculate.V(x)
+    };
+  }
+
+  this.signup = function() {
+    var loginParams = this.update();
+
+    if (account.loginParams) {
+      var extraParams = account.loginParams();
+      for (var attr in extraParams) {
+        loginParams[attr] = extraParams[attr];
+      }
+    }
+
+    return loginParams;
+  };
+
+  this.handshake = function() {
+    return {
+      login: account.login(),
+      A: this.getA()
+    };
+  };
+
+  this.getA = function() {
+    return A;
+  }
+
+  // Delegate login & id so they can be used when talking to the remote
+  this.login = account.login;
+  this.id = account.id;
+
+  // Calculate S, M, and M2
+  // This is the client side of the SRP specification
+  this.calculations = function(salt, ephemeral)
+  {
+    //S -> C: s | B
+    var B = calculate.zeroPrefix(ephemeral);
+    salt = calculate.zeroPrefix(salt);
+    var x = calculate.X(account.login(), account.password(), salt);
+    S = calculate.S(a, A, B, x);
+    K = calculate.K(S);
+
+    // M = H(H(N) xor H(g), H(I), s, A, B, K)
+    var xor = calculate.nXorG();
+    var hash_i = calculate.hash(account.login())
+    M = calculate.hashHex(xor + hash_i + salt + A + B + K);
+    //M2 = H(A, M, K)
+    M2 = calculate.hashHex(A + M + K);
+  };
+
+
+  this.getS = function() {
+    return S;
+  }
+
+  this.getM = function() {
+    return M;
+  }
+
+  this.validate = function(serverM2) {
+    authenticated = (serverM2 && serverM2 == M2)
+    return authenticated;
+  }
+
+  // If someone wants to use the session key for encrypting traffic, they can
+  // access the key with this function.
+  this.key = function()
+  {
+    if(K) {
+      return K;
+    } else {
+      this.onError("User has not been authenticated.");
+    }
+  };
+
+  // Encrypt plaintext using slowAES
+  this.encrypt = function(plaintext)
+  {
+    var key = cryptoHelpers.toNumbers(session.key());
+    var byteMessage = cryptoHelpers.convertStringToByteArray(plaintext);
+    var iv = new Array(16);
+    rng.nextBytes(iv);
+    var paddedByteMessage = slowAES.getPaddedBlock(byteMessage, 0, byteMessage.length, slowAES.modeOfOperation.CFB);
+    var ciphertext = slowAES.encrypt(paddedByteMessage, slowAES.modeOfOperation.CFB, key, key.length, iv).cipher;
+    var retstring = cryptoHelpers.base64.encode(iv.concat(ciphertext));
+    while(retstring.indexOf("+",0) > -1)
+      retstring = retstring.replace("+", "_");
+    return retstring;
+  };
+};
+