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120 lines
4.8 KiB
120 lines
4.8 KiB
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
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/* SHA-1 (FIPS 180-4) implementation in JavaScript (c) Chris Veness 2002-2016 */ |
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/* MIT Licence */ |
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/* www.movable-type.co.uk/scripts/sha1.html */ |
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/* */ |
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/* - see http://csrc.nist.gov/groups/ST/toolkit/secure_hashing.html */ |
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/* http://csrc.nist.gov/groups/ST/toolkit/examples.html */ |
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |
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'use strict'; |
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function f(s, x, y, z) { |
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switch (s) { |
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case 0: return (x & y) ^ (~x & z); // Ch() |
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case 1: return x ^ y ^ z; // Parity() |
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case 2: return (x & y) ^ (x & z) ^ (y & z); // Maj() |
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case 3: return x ^ y ^ z; // Parity() |
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} |
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} |
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function ROTL(x, n) { |
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return (x<<n) | (x>>>(32-n)); |
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} |
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var Sha1 = {}; |
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Sha1.hash = function(msg, options) { |
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var defaults = { msgFormat: 'string', outFormat: 'hex' }; |
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var opt = Object.assign(defaults, options); |
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switch (opt.msgFormat) { |
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default: // default is to convert string to UTF-8, as SHA only deals with byte-streams |
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case 'string': msg = Sha1.utf8Encode(msg); break; |
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case 'hex-bytes':msg = Sha1.hexBytesToString(msg); break; // mostly for running tests |
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} |
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// constants [¤4.2.1] |
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var K = [ 0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6 ]; |
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// initial hash value [¤5.3.1] |
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var H = [ 0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0 ]; |
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// PREPROCESSING [¤6.1.1] |
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msg += String.fromCharCode(0x80); // add trailing '1' bit (+ 0's padding) to string [¤5.1.1] |
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// convert string msg into 512-bit/16-integer blocks arrays of ints [¤5.2.1] |
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var l = msg.length/4 + 2; // length (in 32-bit integers) of msg + Ô1Õ + appended length |
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var N = Math.ceil(l/16); // number of 16-integer-blocks required to hold 'l' ints |
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var M = new Array(N); |
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for (var i=0; i<N; i++) { |
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M[i] = new Array(16); |
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for (var j=0; j<16; j++) { // encode 4 chars per integer, big-endian encoding |
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M[i][j] = (msg.charCodeAt(i*64+j*4)<<24) | (msg.charCodeAt(i*64+j*4+1)<<16) | |
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(msg.charCodeAt(i*64+j*4+2)<<8) | (msg.charCodeAt(i*64+j*4+3)); |
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} // note running off the end of msg is ok 'cos bitwise ops on NaN return 0 |
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} |
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// add length (in bits) into final pair of 32-bit integers (big-endian) [¤5.1.1] |
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// note: most significant word would be (len-1)*8 >>> 32, but since JS converts |
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// bitwise-op args to 32 bits, we need to simulate this by arithmetic operators |
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M[N-1][14] = ((msg.length-1)*8) / Math.pow(2, 32); M[N-1][14] = Math.floor(M[N-1][14]); |
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M[N-1][15] = ((msg.length-1)*8) & 0xffffffff; |
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// HASH COMPUTATION [¤6.1.2] |
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for (var i=0; i<N; i++) { |
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var W = new Array(80); |
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// 1 - prepare message schedule 'W' |
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for (var t=0; t<16; t++) W[t] = M[i][t]; |
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for (var t=16; t<80; t++) W[t] = ROTL(W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16], 1); |
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// 2 - initialise five working variables a, b, c, d, e with previous hash value |
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var a = H[0], b = H[1], c = H[2], d = H[3], e = H[4]; |
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// 3 - main loop (use JavaScript '>>> 0' to emulate UInt32 variables) |
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for (var t=0; t<80; t++) { |
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var s = Math.floor(t/20); // seq for blocks of 'f' functions and 'K' constants |
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var T = (ROTL(a,5) + f(s,b,c,d) + e + K[s] + W[t]) >>> 0; |
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e = d; |
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d = c; |
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c = ROTL(b, 30) >>> 0; |
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b = a; |
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a = T; |
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} |
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// 4 - compute the new intermediate hash value (note 'addition modulo 2^32' Ð JavaScript |
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// '>>> 0' coerces to unsigned UInt32 which achieves modulo 2^32 addition) |
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H[0] = (H[0]+a) >>> 0; |
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H[1] = (H[1]+b) >>> 0; |
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H[2] = (H[2]+c) >>> 0; |
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H[3] = (H[3]+d) >>> 0; |
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H[4] = (H[4]+e) >>> 0; |
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} |
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// convert H0..H4 to hex strings (with leading zeros) |
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for (var h=0; h<H.length; h++) H[h] = ('00000000'+H[h].toString(16)).slice(-8); |
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// concatenate H0..H4, with separator if required |
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var separator = opt.outFormat=='hex-w' ? ' ' : ''; |
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return H.join(separator); |
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}; |
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Sha1.utf8Encode = function(str) { |
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return unescape(encodeURIComponent(str)); |
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}; |
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Sha1.hexBytesToString = function(hexStr) { |
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hexStr = hexStr.replace(' ', ''); // allow space-separated groups |
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var str = ''; |
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for (var i=0; i<hexStr.length; i+=2) { |
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str += String.fromCharCode(parseInt(hexStr.slice(i, i+2), 16)); |
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} |
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return str; |
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}; |
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module.exports = Sha1; // CommonJs export
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