initial commit for GitHub

core/hmac.js

@@ -0,0 +1,40 @@
+/** @fileOverview HMAC implementation.
+ *
+ * @author Emily Stark
+ * @author Mike Hamburg
+ * @author Dan Boneh
+ */
+
+/** HMAC with the specified hash function.
+ * @constructor
+ * @param {bitArray} key the key for HMAC.
+ * @param {Object} [hash=sjcl.hash.sha256] The hash function to use.
+ */
+sjcl.misc.hmac = function (key, Hash) {
+  this._hash = Hash = Hash || sjcl.hash.sha256;
+  var exKey = [[],[]], i,
+      bs = Hash.prototype.blockSize / 32;
+  this._baseHash = [new Hash(), new Hash()];
+
+  if (key.length > bs) {
+    key = Hash.hash(key);
+  }
+  
+  for (i=0; i<bs; i++) {
+    exKey[0][i] = key[i]^0x36363636;
+    exKey[1][i] = key[i]^0x5C5C5C5C;
+  }
+  
+  this._baseHash[0].update(exKey[0]);
+  this._baseHash[1].update(exKey[1]);
+};
+
+/** HMAC with the specified hash function.  Also called encrypt since it's a prf.
+ * @param {bitArray|String} data The data to mac.
+ * @param {Codec} [encoding] the encoding function to use.
+ */
+sjcl.misc.hmac.prototype.encrypt = sjcl.misc.hmac.prototype.mac = function (data, encoding) {
+  var w = new (this._hash)(this._baseHash[0]).update(data, encoding).finalize();
+  return new (this._hash)(this._baseHash[1]).update(w).finalize();
+};
+