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/*
CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
(function () {
// Shortcuts
var C = CryptoJS;
var C_lib = C.lib;
var Base = C_lib.Base;
var WordArray = C_lib.WordArray;
var C_algo = C.algo;
var MD5 = C_algo.MD5;
/**
* This key derivation function is meant to conform with EVP_BytesToKey.
* www.openssl.org/docs/crypto/EVP_BytesToKey.html
*/
var EvpKDF = C_algo.EvpKDF = Base.extend({
/**
* Configuration options.
*
* @property {number} keySize The key size in words to generate. Default: 4 (128 bits)
* @property {Hasher} hasher The hash algorithm to use. Default: MD5
* @property {number} iterations The number of iterations to perform. Default: 1
*/
cfg: Base.extend({
keySize: 128/32,
hasher: MD5,
iterations: 1
}),
/**
* Initializes a newly created key derivation function.
*
* @param {Object} cfg (Optional) The configuration options to use for the derivation.
*
* @example
*
* var kdf = CryptoJS.algo.EvpKDF.create();
* var kdf = CryptoJS.algo.EvpKDF.create({ keySize: 8 });
* var kdf = CryptoJS.algo.EvpKDF.create({ keySize: 8, iterations: 1000 });
*/
init: function (cfg) {
this.cfg = this.cfg.extend(cfg);
},
/**
* Derives a key from a password.
*
* @param {WordArray|string} password The password.
* @param {WordArray|string} salt A salt.
*
* @return {WordArray} The derived key.
*
* @example
*
* var key = kdf.compute(password, salt);
*/
compute: function (password, salt) {
// Shortcut
var cfg = this.cfg;
// Init hasher
var hasher = cfg.hasher.create();
// Initial values
var derivedKey = WordArray.create();
// Shortcuts
var derivedKeyWords = derivedKey.words;
var keySize = cfg.keySize;
var iterations = cfg.iterations;
// Generate key
while (derivedKeyWords.length < keySize) {
if (block) {
hasher.update(block);
}
var block = hasher.update(password).finalize(salt);
hasher.reset();
// Iterations
for (var i = 1; i < iterations; i++) {
block = hasher.finalize(block);
hasher.reset();
}
derivedKey.concat(block);
}
derivedKey.sigBytes = keySize * 4;
return derivedKey;
}
});
/**
* Derives a key from a password.
*
* @param {WordArray|string} password The password.
* @param {WordArray|string} salt A salt.
* @param {Object} cfg (Optional) The configuration options to use for this computation.
*
* @return {WordArray} The derived key.
*
* @static
*
* @example
*
* var key = CryptoJS.EvpKDF(password, salt);
* var key = CryptoJS.EvpKDF(password, salt, { keySize: 8 });
* var key = CryptoJS.EvpKDF(password, salt, { keySize: 8, iterations: 1000 });
*/
C.EvpKDF = function (password, salt, cfg) {
return EvpKDF.create(cfg).compute(password, salt);
};
}());
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