177 lines
6.6 KiB
JavaScript
177 lines
6.6 KiB
JavaScript
/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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/* SHA-1 implementation in JavaScript | (c) Chris Veness 2002-2010 | www.movable-type.co.uk */
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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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var Sha1 = {}; // Sha1 namespace
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/**
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* Generates SHA-1 hash of string
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*
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* @param {String} msg String to be hashed
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* @param {Boolean} [utf8encode=true] Encode msg as UTF-8 before generating hash
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* @returns {String} Hash of msg as hex character string
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*/
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Sha1.hash = function(msg, utf8encode) {
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utf8encode = (typeof utf8encode == 'undefined') ? true : utf8encode;
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// convert string to UTF-8, as SHA only deals with byte-streams
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if (utf8encode) msg = Utf8.encode(msg);
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// constants [§4.2.1]
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var K = [0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6];
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// PREPROCESSING
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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 + ‘1’ + 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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// set initial hash value [§5.3.1]
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var H0 = 0x67452301;
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var H1 = 0xefcdab89;
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var H2 = 0x98badcfe;
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var H3 = 0x10325476;
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var H4 = 0xc3d2e1f0;
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// HASH COMPUTATION [§6.1.2]
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var W = new Array(80); var a, b, c, d, e;
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for (var i=0; i<N; i++) {
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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] = Sha1.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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a = H0; b = H1; c = H2; d = H3; e = H4;
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// 3 - main loop
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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 = (Sha1.ROTL(a,5) + Sha1.f(s,b,c,d) + e + K[s] + W[t]) & 0xffffffff;
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e = d;
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d = c;
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c = Sha1.ROTL(b, 30);
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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
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H0 = (H0+a) & 0xffffffff; // note 'addition modulo 2^32'
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H1 = (H1+b) & 0xffffffff;
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H2 = (H2+c) & 0xffffffff;
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H3 = (H3+d) & 0xffffffff;
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H4 = (H4+e) & 0xffffffff;
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}
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return Sha1.toHexStr(H0) + Sha1.toHexStr(H1) +
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Sha1.toHexStr(H2) + Sha1.toHexStr(H3) + Sha1.toHexStr(H4);
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}
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//
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// function 'f' [§4.1.1]
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//
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Sha1.f = function(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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//
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// rotate left (circular left shift) value x by n positions [§3.2.5]
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//
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Sha1.ROTL = function(x, n) {
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return (x<<n) | (x>>>(32-n));
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}
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//
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// hexadecimal representation of a number
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// (note toString(16) is implementation-dependant, and
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// in IE returns signed numbers when used on full words)
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//
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Sha1.toHexStr = function(n) {
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var s="", v;
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for (var i=7; i>=0; i--) { v = (n>>>(i*4)) & 0xf; s += v.toString(16); }
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return s;
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}
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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/* Utf8 class: encode / decode between multi-byte Unicode characters and UTF-8 multiple */
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/* single-byte character encoding (c) Chris Veness 2002-2010 */
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
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var Utf8 = {}; // Utf8 namespace
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/**
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* Encode multi-byte Unicode string into utf-8 multiple single-byte characters
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* (BMP / basic multilingual plane only)
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*
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* Chars in range U+0080 - U+07FF are encoded in 2 chars, U+0800 - U+FFFF in 3 chars
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*
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* @param {String} strUni Unicode string to be encoded as UTF-8
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* @returns {String} encoded string
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*/
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Utf8.encode = function(strUni) {
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// use regular expressions & String.replace callback function for better efficiency
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// than procedural approaches
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var strUtf = strUni.replace(
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/[\u0080-\u07ff]/g, // U+0080 - U+07FF => 2 bytes 110yyyyy, 10zzzzzz
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function(c) {
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var cc = c.charCodeAt(0);
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return String.fromCharCode(0xc0 | cc>>6, 0x80 | cc&0x3f); }
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);
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strUtf = strUtf.replace(
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/[\u0800-\uffff]/g, // U+0800 - U+FFFF => 3 bytes 1110xxxx, 10yyyyyy, 10zzzzzz
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function(c) {
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var cc = c.charCodeAt(0);
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return String.fromCharCode(0xe0 | cc>>12, 0x80 | cc>>6&0x3F, 0x80 | cc&0x3f); }
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);
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return strUtf;
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}
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/**
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* Decode utf-8 encoded string back into multi-byte Unicode characters
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*
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* @param {String} strUtf UTF-8 string to be decoded back to Unicode
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* @returns {String} decoded string
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*/
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Utf8.decode = function(strUtf) {
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// note: decode 3-byte chars first as decoded 2-byte strings could appear to be 3-byte char!
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var strUni = strUtf.replace(
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/[\u00e0-\u00ef][\u0080-\u00bf][\u0080-\u00bf]/g, // 3-byte chars
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function(c) { // (note parentheses for precence)
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var cc = ((c.charCodeAt(0)&0x0f)<<12) | ((c.charCodeAt(1)&0x3f)<<6) | ( c.charCodeAt(2)&0x3f);
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return String.fromCharCode(cc); }
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);
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strUni = strUni.replace(
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/[\u00c0-\u00df][\u0080-\u00bf]/g, // 2-byte chars
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function(c) { // (note parentheses for precence)
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var cc = (c.charCodeAt(0)&0x1f)<<6 | c.charCodeAt(1)&0x3f;
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return String.fromCharCode(cc); }
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);
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return strUni;
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}
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/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |