File size: 3,993 Bytes
7d73cf2
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
;(function (root, factory, undef) {
	if (typeof exports === "object") {
		// CommonJS
		module.exports = exports = factory(require("./core"), require("./sha1"), require("./hmac"));
	}
	else if (typeof define === "function" && define.amd) {
		// AMD
		define(["./core", "./sha1", "./hmac"], factory);
	}
	else {
		// Global (browser)
		factory(root.CryptoJS);
	}
}(this, function (CryptoJS) {

	(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) {
	            var block;

	            // 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);
	                }
	                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);
	    };
	}());


	return CryptoJS.EvpKDF;

}));