filer/lib/crypto-js/components/sha256.js

175 lines
4.9 KiB
JavaScript

/*
CryptoJS v3.0.2
code.google.com/p/crypto-js
(c) 2009-2012 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
(function (Math) {
// Shortcuts
var C = CryptoJS;
var C_lib = C.lib;
var WordArray = C_lib.WordArray;
var Hasher = C_lib.Hasher;
var C_algo = C.algo;
// Initialization and round constants tables
var H = [];
var K = [];
// Compute constants
(function () {
function isPrime(n) {
var sqrtN = Math.sqrt(n);
for (var factor = 2; factor <= sqrtN; factor++) {
if (!(n % factor)) {
return false;
}
}
return true;
}
function getFractionalBits(n) {
return ((n - (n | 0)) * 0x100000000) | 0;
}
var n = 2;
var nPrime = 0;
while (nPrime < 64) {
if (isPrime(n)) {
if (nPrime < 8) {
H[nPrime] = getFractionalBits(Math.pow(n, 1 / 2));
}
K[nPrime] = getFractionalBits(Math.pow(n, 1 / 3));
nPrime++;
}
n++;
}
}());
// Reusable object
var W = [];
/**
* SHA-256 hash algorithm.
*/
var SHA256 = C_algo.SHA256 = Hasher.extend({
_doReset: function () {
this._hash = WordArray.create(H.slice(0));
},
_doProcessBlock: function (M, offset) {
// Shortcut
var H = this._hash.words;
// Working variables
var a = H[0];
var b = H[1];
var c = H[2];
var d = H[3];
var e = H[4];
var f = H[5];
var g = H[6];
var h = H[7];
// Computation
for (var i = 0; i < 64; i++) {
if (i < 16) {
W[i] = M[offset + i] | 0;
} else {
var gamma0x = W[i - 15];
var gamma0 = ((gamma0x << 25) | (gamma0x >>> 7)) ^
((gamma0x << 14) | (gamma0x >>> 18)) ^
(gamma0x >>> 3);
var gamma1x = W[i - 2];
var gamma1 = ((gamma1x << 15) | (gamma1x >>> 17)) ^
((gamma1x << 13) | (gamma1x >>> 19)) ^
(gamma1x >>> 10);
W[i] = gamma0 + W[i - 7] + gamma1 + W[i - 16];
}
var ch = (e & f) ^ (~e & g);
var maj = (a & b) ^ (a & c) ^ (b & c);
var sigma0 = ((a << 30) | (a >>> 2)) ^ ((a << 19) | (a >>> 13)) ^ ((a << 10) | (a >>> 22));
var sigma1 = ((e << 26) | (e >>> 6)) ^ ((e << 21) | (e >>> 11)) ^ ((e << 7) | (e >>> 25));
var t1 = h + sigma1 + ch + K[i] + W[i];
var t2 = sigma0 + maj;
h = g;
g = f;
f = e;
e = (d + t1) | 0;
d = c;
c = b;
b = a;
a = (t1 + t2) | 0;
}
// Intermediate hash value
H[0] = (H[0] + a) | 0;
H[1] = (H[1] + b) | 0;
H[2] = (H[2] + c) | 0;
H[3] = (H[3] + d) | 0;
H[4] = (H[4] + e) | 0;
H[5] = (H[5] + f) | 0;
H[6] = (H[6] + g) | 0;
H[7] = (H[7] + h) | 0;
},
_doFinalize: function () {
// Shortcuts
var data = this._data;
var dataWords = data.words;
var nBitsTotal = this._nDataBytes * 8;
var nBitsLeft = data.sigBytes * 8;
// Add padding
dataWords[nBitsLeft >>> 5] |= 0x80 << (24 - nBitsLeft % 32);
dataWords[(((nBitsLeft + 64) >>> 9) << 4) + 15] = nBitsTotal;
data.sigBytes = dataWords.length * 4;
// Hash final blocks
this._process();
}
});
/**
* Shortcut function to the hasher's object interface.
*
* @param {WordArray|string} message The message to hash.
*
* @return {WordArray} The hash.
*
* @static
*
* @example
*
* var hash = CryptoJS.SHA256('message');
* var hash = CryptoJS.SHA256(wordArray);
*/
C.SHA256 = Hasher._createHelper(SHA256);
/**
* Shortcut function to the HMAC's object interface.
*
* @param {WordArray|string} message The message to hash.
* @param {WordArray|string} key The secret key.
*
* @return {WordArray} The HMAC.
*
* @static
*
* @example
*
* var hmac = CryptoJS.HmacSHA256(message, key);
*/
C.HmacSHA256 = Hasher._createHmacHelper(SHA256);
}(Math));