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