1/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 2/* SHA-256 implementation in JavaScript (c) Chris Veness 2002-2014 / MIT Licence */ 3/* */ 4/* - see http://csrc.nist.gov/groups/ST/toolkit/secure_hashing.html */ 5/* http://csrc.nist.gov/groups/ST/toolkit/examples.html */ 6/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 7 8/* jshint node:true *//* global define, escape, unescape */ 9'use strict'; 10 11 12/** 13 * SHA-256 hash function reference implementation. 14 * 15 * @namespace 16 */ 17var Sha256 = {}; 18 19 20/** 21 * Generates SHA-256 hash of string. 22 * 23 * @param {string} msg - String to be hashed 24 * @returns {string} Hash of msg as hex character string 25 */ 26Sha256.hash = function(msg) { 27 // convert string to UTF-8, as SHA only deals with byte-streams 28 msg = msg.utf8Encode(); 29 30 // constants [§4.2.2] 31 var K = [ 32 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 33 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 34 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, 35 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 36 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 37 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 38 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, 39 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2 ]; 40 // initial hash value [§5.3.1] 41 var H = [
42 0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19 ]; 43 44 // PREPROCESSING 45 46 msg += String.fromCharCode(0x80); // add trailing '1' bit (+ 0's padding) to string [§5.1.1] 47 48 // convert string msg into 512-bit/16-integer blocks arrays of ints [§5.2.1] 49 var l = msg.length/4 + 2; // length (in 32-bit integers) of msg + â1â + appended length 50 var N = Math.ceil(l/16); // number of 16-integer-blocks required to hold 'l' ints 51 var M = new Array(N); 52 53 for (var i=0; i<N; i++) { 54 M[i] = new Array(16); 55 for (var j=0; j<16; j++) { // encode 4 chars per integer, big-endian encoding 56 M[i][j] = (msg.charCodeAt(i*64+j*4)<<24) | (msg.charCodeAt(i*64+j*4+1)<<16) | 57 (msg.charCodeAt(i*64+j*4+2)<<8) | (msg.charCodeAt(i*64+j*4+3)); 58 } // note running off the end of msg is ok 'cos bitwise ops on NaN return 0 59 } 60 // add length (in bits) into final pair of 32-bit integers (big-endian) [§5.1.1] 61 // note: most significant word would be (len-1)*8 >>> 32, but since JS converts 62 // bitwise-op args to 32 bits, we need to simulate this by arithmetic operators 63 M[N-1][14] = ((msg.length-1)*8) / Math.pow(2, 32); M[N-1][14] = Math.floor(M[N-1][14]); 64 M[N-1][15] = ((msg.length-1)*8) & 0xffffffff; 65 66 67 // HASH COMPUTATION [§6.1.2] 68 69 var W = new Array(64); var a, b, c, d, e, f, g, h; 70 for (var i=0; i<N; i++) { 71 72 // 1 - prepare message schedule 'W' 73 for (var t=0; t<16; t++) W[t] = M[i][t]; 74 for (var t=16; t<64; t++) W[t] = (Sha256.Ï1(W[t-2]) + W[t-7] + Sha256.Ï0(W[t-15]) + W[t-16]) & 0xffffffff; 75 76 // 2 - initialise working variables a, b, c, d, e, f, g, h with previous hash value 77 a = H[0]; b = H[1]; c = H[2]; d = H[3]; e = H[4]; f = H[5]; g = H[6]; h = H[7]; 78 79 // 3 - main loop (note 'addition modulo 2^32') 80 for (var t=0; t<64; t++) { 81 var T1 = h + Sha256.Σ1(e) + Sha256.Ch(e, f, g) + K[t] + W[t]; 82 var T2 = Sha256.Σ0(a) + Sha256.Maj(a, b, c); 83 h = g; 84 g = f; 85 f = e; 86 e = (d + T1) & 0xffffffff; 87 d = c; 88 c = b; 89 b = a; 90 a = (T1 + T2) & 0xffffffff; 91 } 92 // 4 - compute the new intermediate hash value (note 'addition modulo 2^32') 93 H[0] = (H[0]+a) & 0xffffffff; 94 H[1] = (H[1]+b) & 0xffffffff; 95 H[2] = (H[2]+c) & 0xffffffff; 96 H[3] = (H[3]+d) & 0xffffffff; 97 H[4] = (H[4]+e) & 0xffffffff; 98 H[5] = (H[5]+f) & 0xffffffff; 99 H[6] = (H[6]+g) & 0xffffffff; 100 H[7] = (H[7]+h) & 0xffffffff; 101 } 102 103 return Sha256.toHexStr(H[0]) + Sha256.toHexStr(H[1]) + Sha256.toHexStr(H[2]) + Sha256.toHexStr(H[3]) + 104 Sha256.toHexStr(H[4]) + Sha256.toHexStr(H[5]) + Sha256.toHexStr(H[6]) + Sha256.toHexStr(H[7]); 105}; 106 107 108/** 109 * Rotates right (circular right shift) value x by n positions [§3.2.4]. 110 * @private 111 */ 112Sha256.ROTR = function(n, x) { 113 return (x >>> n) | (x << (32-n)); 114}; 115 116/** 117 * Logical functions [§4.1.2]. 118 * @private 119 */ 120Sha256.Σ0 = function(x) { return Sha256.ROTR(2, x) ^ Sha256.ROTR(13, x) ^ Sha256.ROTR(22, x); }; 121Sha256.Σ1 = function(x) { return Sha256.ROTR(6, x) ^ Sha256.ROTR(11, x) ^ Sha256.ROTR(25, x); }; 122Sha256.Ï0 = function(x) { return Sha256.ROTR(7, x) ^ Sha256.ROTR(18, x) ^ (x>>>3); }; 123Sha256.Ï1 = function(x) { return Sha256.ROTR(17, x) ^ Sha256.ROTR(19, x) ^ (x>>>10); }; 124Sha256.Ch = function(x, y, z) { return (x & y) ^ (~x & z); }; 125Sha256.Maj = function(x, y, z) { return (x & y) ^ (x & z) ^ (y & z); }; 126 127 128/** 129 * Hexadecimal representation of a number. 130 * @private 131 */ 132Sha256.toHexStr = function(n) { 133 // note can't use toString(16) as it is implementation-dependant, 134 // and in IE returns signed numbers when used on full words 135 var s="", v; 136 for (var i=7; i>=0; i--) { v = (n>>>(i*4)) & 0xf; s += v.toString(16); } 137 return s; 138}; 139 140 141/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 142 143 144/** Extend String object with method to encode multi-byte string to utf8 145 * - monsur.hossa.in/2012/07/20/utf-8-in-javascript.html */ 146if (typeof String.prototype.utf8Encode == 'undefined') { 147 String.prototype.utf8Encode = function() { 148 return unescape( encodeURIComponent( this ) ); 149 }; 150} 151 152/** Extend String object with method to decode utf8 string to multi-byte */ 153if (typeof String.prototype.utf8Decode == 'undefined') { 154 String.prototype.utf8Decode = function() { 155 try { 156 return decodeURIComponent( escape( this ) ); 157 } catch (e) { 158 return this; // invalid UTF-8? return as-is 159 } 160 }; 161} 162 163 164/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ 165if (typeof module != 'undefined' && module.exports) module.exports = Sha256; // CommonJs export 166if (typeof define == 'function' && define.amd) define([], function() { return Sha256; }); // AMD
Line numbers count LF bytes from the start of the resource, as the search results do. Vendor segments are library code the classifier recognised; they are stored but not indexed. Bytes are shown as Latin1 characters, one per byte.