From b55ed280ddadcf9245af56658e28de0112bfe939 Mon Sep 17 00:00:00 2001
From: Quinn Slack <sqs@cs.stanford.edu>
Date: Tue, 19 Apr 2011 05:14:44 -0700
Subject: [PATCH] srp implementation

---
 core/srp.js | 93 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 core/srp.js

diff --git a/core/srp.js b/core/srp.js
new file mode 100644
index 00000000..417cd5ed
--- /dev/null
+++ b/core/srp.js
@@ -0,0 +1,93 @@
+/** @fileOverview Javascript SRP implementation.
+ *
+ * @author Quinn Slack
+ */
+
+/**
+ * Compute the SRP verifier from the username, password, salt, and group.
+ * @class SRP
+ */
+sjcl.keyexchange.srp = {
+  makeVerifier: function(I, P, s, N, g) {
+    var x;
+    // From RFC 5054:
+    // v = g^x mod N
+    x = this.makeX(I, P, s);
+    x = sjcl.bn.fromBits(x);
+    return g.powermod(x, N);
+  },
+
+  makeX: function(I, P, s) {
+    var inner;
+    // From RFC 2945:
+    // x = SHA1(<salt> | SHA(<username> | ":" | <raw password>))
+    inner = sjcl.hash.sha1.hash(I + ':' + P);
+    return sjcl.hash.sha1.hash(sjcl.bitArray.concat(s, inner));
+  },
+
+  /**
+   * Returns the known SRP group with the given size (in bits).
+   * @param {String} i The size of the known SRP group.
+   * @return {Object} An object with "N" and "g" properties.
+   */
+  knownGroup:function(i) {
+    if (typeof i !== "string") { i = i.toString(); }
+    if (!this._didInitKnownGroups) { this._initKnownGroups(); }
+    return this._knownGroups[i];
+  },
+
+  /**
+   * Initializes bignum objects for known group parameters.
+   * @private
+   */
+  _didInitKnownGroups: false,
+  _initKnownGroups:function() {
+    var i, size, group;
+    for (i=0; i < this._knownGroupSizes.length; i++) {
+      size = this._knownGroupSizes[i].toString();
+      group = this._knownGroups[size];
+      group.N = new sjcl.bn(group.N);
+      group.g = new sjcl.bn(group.g);
+    }
+    this._didInitKnownGroups = true;
+  },
+
+  _knownGroupSizes: [1024, 1536, 2048],
+  _knownGroups: {
+    1024: {
+      N: "EEAF0AB9ADB38DD69C33F80AFA8FC5E86072618775FF3C0B9EA2314C" +
+         "9C256576D674DF7496EA81D3383B4813D692C6E0E0D5D8E250B98BE4" +
+         "8E495C1D6089DAD15DC7D7B46154D6B6CE8EF4AD69B15D4982559B29" +
+         "7BCF1885C529F566660E57EC68EDBC3C05726CC02FD4CBF4976EAA9A" +
+         "FD5138FE8376435B9FC61D2FC0EB06E3",
+      g:2
+    },
+
+    1536: {
+      N: "9DEF3CAFB939277AB1F12A8617A47BBBDBA51DF499AC4C80BEEEA961" +
+         "4B19CC4D5F4F5F556E27CBDE51C6A94BE4607A291558903BA0D0F843" +
+         "80B655BB9A22E8DCDF028A7CEC67F0D08134B1C8B97989149B609E0B" +
+         "E3BAB63D47548381DBC5B1FC764E3F4B53DD9DA1158BFD3E2B9C8CF5" +
+         "6EDF019539349627DB2FD53D24B7C48665772E437D6C7F8CE442734A" +
+         "F7CCB7AE837C264AE3A9BEB87F8A2FE9B8B5292E5A021FFF5E91479E" +
+         "8CE7A28C2442C6F315180F93499A234DCF76E3FED135F9BB",
+      g: 2
+    },
+
+    2048: {
+      N: "AC6BDB41324A9A9BF166DE5E1389582FAF72B6651987EE07FC319294" +
+         "3DB56050A37329CBB4A099ED8193E0757767A13DD52312AB4B03310D" +
+         "CD7F48A9DA04FD50E8083969EDB767B0CF6095179A163AB3661A05FB" +
+         "D5FAAAE82918A9962F0B93B855F97993EC975EEAA80D740ADBF4FF74" +
+         "7359D041D5C33EA71D281E446B14773BCA97B43A23FB801676BD207A" +
+         "436C6481F1D2B9078717461A5B9D32E688F87748544523B524B0D57D" +
+         "5EA77A2775D2ECFA032CFBDBF52FB3786160279004E57AE6AF874E73" +
+         "03CE53299CCC041C7BC308D82A5698F3A8D0C38271AE35F8E9DBFBB6" +
+         "94B5C803D89F7AE435DE236D525F54759B65E372FCD68EF20FA7111F" +
+         "9E4AFF73",
+      g: 2
+    }
+  }
+
+};
+