diff options
Diffstat (limited to 'static-files/js/sha256.js')
| -rw-r--r-- | static-files/js/sha256.js | 174 |
1 files changed, 174 insertions, 0 deletions
diff --git a/static-files/js/sha256.js b/static-files/js/sha256.js new file mode 100644 index 0000000..a98498d --- /dev/null +++ b/static-files/js/sha256.js @@ -0,0 +1,174 @@ +/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ +/* SHA-256 implementation in JavaScript | (c) Chris Veness 2002-2010 | www.movable-type.co.uk */ +/* - see http://csrc.nist.gov/groups/ST/toolkit/secure_hashing.html */ +/* http://csrc.nist.gov/groups/ST/toolkit/examples.html */ +/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ + +var Sha256 = {}; // Sha256 namespace + +/** + * Generates SHA-256 hash of string + * + * @param {String} msg String to be hashed + * @param {Boolean} [utf8encode=true] Encode msg as UTF-8 before generating hash + * @returns {String} Hash of msg as hex character string + */ +Sha256.hash = function(msg, utf8encode) { + utf8encode = (typeof utf8encode == 'undefined') ? true : utf8encode; + + // convert string to UTF-8, as SHA only deals with byte-streams + if (utf8encode) msg = Utf8.encode(msg); + + // constants [§4.2.2] + var K = [0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, + 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, + 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, + 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, + 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, + 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, + 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3, + 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2]; + // initial hash value [§5.3.1] + var H = [0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19]; + + // PREPROCESSING + + msg += String.fromCharCode(0x80); // add trailing '1' bit (+ 0's padding) to string [§5.1.1] + + // convert string msg into 512-bit/16-integer blocks arrays of ints [§5.2.1] + var l = msg.length/4 + 2; // length (in 32-bit integers) of msg + ‘1’ + appended length + var N = Math.ceil(l/16); // number of 16-integer-blocks required to hold 'l' ints + var M = new Array(N); + + for (var i=0; i<N; i++) { + M[i] = new Array(16); + for (var j=0; j<16; j++) { // encode 4 chars per integer, big-endian encoding + M[i][j] = (msg.charCodeAt(i*64+j*4)<<24) | (msg.charCodeAt(i*64+j*4+1)<<16) | + (msg.charCodeAt(i*64+j*4+2)<<8) | (msg.charCodeAt(i*64+j*4+3)); + } // note running off the end of msg is ok 'cos bitwise ops on NaN return 0 + } + // add length (in bits) into final pair of 32-bit integers (big-endian) [§5.1.1] + // note: most significant word would be (len-1)*8 >>> 32, but since JS converts + // bitwise-op args to 32 bits, we need to simulate this by arithmetic operators + M[N-1][14] = ((msg.length-1)*8) / Math.pow(2, 32); M[N-1][14] = Math.floor(M[N-1][14]) + M[N-1][15] = ((msg.length-1)*8) & 0xffffffff; + + + // HASH COMPUTATION [§6.1.2] + + var W = new Array(64); var a, b, c, d, e, f, g, h; + for (var i=0; i<N; i++) { + + // 1 - prepare message schedule 'W' + for (var t=0; t<16; t++) W[t] = M[i][t]; + for (var t=16; t<64; t++) W[t] = (Sha256.sigma1(W[t-2]) + W[t-7] + Sha256.sigma0(W[t-15]) + W[t-16]) & 0xffffffff; + + // 2 - initialise working variables a, b, c, d, e, f, g, h with previous hash value + a = H[0]; b = H[1]; c = H[2]; d = H[3]; e = H[4]; f = H[5]; g = H[6]; h = H[7]; + + // 3 - main loop (note 'addition modulo 2^32') + for (var t=0; t<64; t++) { + var T1 = h + Sha256.Sigma1(e) + Sha256.Ch(e, f, g) + K[t] + W[t]; + var T2 = Sha256.Sigma0(a) + Sha256.Maj(a, b, c); + h = g; + g = f; + f = e; + e = (d + T1) & 0xffffffff; + d = c; + c = b; + b = a; + a = (T1 + T2) & 0xffffffff; + } + // 4 - compute the new intermediate hash value (note 'addition modulo 2^32') + H[0] = (H[0]+a) & 0xffffffff; + H[1] = (H[1]+b) & 0xffffffff; + H[2] = (H[2]+c) & 0xffffffff; + H[3] = (H[3]+d) & 0xffffffff; + H[4] = (H[4]+e) & 0xffffffff; + H[5] = (H[5]+f) & 0xffffffff; + H[6] = (H[6]+g) & 0xffffffff; + H[7] = (H[7]+h) & 0xffffffff; + } + + return Sha256.toHexStr(H[0]) + Sha256.toHexStr(H[1]) + Sha256.toHexStr(H[2]) + Sha256.toHexStr(H[3]) + + Sha256.toHexStr(H[4]) + Sha256.toHexStr(H[5]) + Sha256.toHexStr(H[6]) + Sha256.toHexStr(H[7]); +} + +Sha256.ROTR = function(n, x) { return (x >>> n) | (x << (32-n)); } +Sha256.Sigma0 = function(x) { return Sha256.ROTR(2, x) ^ Sha256.ROTR(13, x) ^ Sha256.ROTR(22, x); } +Sha256.Sigma1 = function(x) { return Sha256.ROTR(6, x) ^ Sha256.ROTR(11, x) ^ Sha256.ROTR(25, x); } +Sha256.sigma0 = function(x) { return Sha256.ROTR(7, x) ^ Sha256.ROTR(18, x) ^ (x>>>3); } +Sha256.sigma1 = function(x) { return Sha256.ROTR(17, x) ^ Sha256.ROTR(19, x) ^ (x>>>10); } +Sha256.Ch = function(x, y, z) { return (x & y) ^ (~x & z); } +Sha256.Maj = function(x, y, z) { return (x & y) ^ (x & z) ^ (y & z); } + +// +// hexadecimal representation of a number +// (note toString(16) is implementation-dependant, and +// in IE returns signed numbers when used on full words) +// +Sha256.toHexStr = function(n) { + var s="", v; + for (var i=7; i>=0; i--) { v = (n>>>(i*4)) & 0xf; s += v.toString(16); } + return s; +} + + +/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ +/* Utf8 class: encode / decode between multi-byte Unicode characters and UTF-8 multiple */ +/* single-byte character encoding (c) Chris Veness 2002-2010 */ +/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ + +var Utf8 = {}; // Utf8 namespace + +/** + * Encode multi-byte Unicode string into utf-8 multiple single-byte characters + * (BMP / basic multilingual plane only) + * + * Chars in range U+0080 - U+07FF are encoded in 2 chars, U+0800 - U+FFFF in 3 chars + * + * @param {String} strUni Unicode string to be encoded as UTF-8 + * @returns {String} encoded string + */ +Utf8.encode = function(strUni) { + // use regular expressions & String.replace callback function for better efficiency + // than procedural approaches + var strUtf = strUni.replace( + /[\u0080-\u07ff]/g, // U+0080 - U+07FF => 2 bytes 110yyyyy, 10zzzzzz + function(c) { + var cc = c.charCodeAt(0); + return String.fromCharCode(0xc0 | cc>>6, 0x80 | cc&0x3f); } + ); + strUtf = strUtf.replace( + /[\u0800-\uffff]/g, // U+0800 - U+FFFF => 3 bytes 1110xxxx, 10yyyyyy, 10zzzzzz + function(c) { + var cc = c.charCodeAt(0); + return String.fromCharCode(0xe0 | cc>>12, 0x80 | cc>>6&0x3F, 0x80 | cc&0x3f); } + ); + return strUtf; +} + +/** + * Decode utf-8 encoded string back into multi-byte Unicode characters + * + * @param {String} strUtf UTF-8 string to be decoded back to Unicode + * @returns {String} decoded string + */ +Utf8.decode = function(strUtf) { + // note: decode 3-byte chars first as decoded 2-byte strings could appear to be 3-byte char! + var strUni = strUtf.replace( + /[\u00e0-\u00ef][\u0080-\u00bf][\u0080-\u00bf]/g, // 3-byte chars + function(c) { // (note parentheses for precence) + var cc = ((c.charCodeAt(0)&0x0f)<<12) | ((c.charCodeAt(1)&0x3f)<<6) | ( c.charCodeAt(2)&0x3f); + return String.fromCharCode(cc); } + ); + strUni = strUni.replace( + /[\u00c0-\u00df][\u0080-\u00bf]/g, // 2-byte chars + function(c) { // (note parentheses for precence) + var cc = (c.charCodeAt(0)&0x1f)<<6 | c.charCodeAt(1)&0x3f; + return String.fromCharCode(cc); } + ); + return strUni; +} + +/* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */ |