paste.chapril.org-privatebin/core/hmac.js
2010-05-26 15:34:42 -07:00

41 lines
1.1 KiB
JavaScript

/** @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();
};