| /** |
| * Secure Hash Algorithm with 256-bit digest (SHA-256) implementation. |
| * |
| * See FIPS 180-2 for details. |
| * |
| * @author Dave Longley |
| * |
| * Copyright (c) 2010-2015 Digital Bazaar, Inc. |
| */ |
| var forge = require('./forge'); |
| require('./md'); |
| require('./util'); |
| |
| var sha256 = module.exports = forge.sha256 = forge.sha256 || {}; |
| forge.md.sha256 = forge.md.algorithms.sha256 = sha256; |
| |
| /** |
| * Creates a SHA-256 message digest object. |
| * |
| * @return a message digest object. |
| */ |
| sha256.create = function() { |
| // do initialization as necessary |
| if(!_initialized) { |
| _init(); |
| } |
| |
| // SHA-256 state contains eight 32-bit integers |
| var _state = null; |
| |
| // input buffer |
| var _input = forge.util.createBuffer(); |
| |
| // used for word storage |
| var _w = new Array(64); |
| |
| // message digest object |
| var md = { |
| algorithm: 'sha256', |
| blockLength: 64, |
| digestLength: 32, |
| // 56-bit length of message so far (does not including padding) |
| messageLength: 0, |
| // true message length |
| fullMessageLength: null, |
| // size of message length in bytes |
| messageLengthSize: 8 |
| }; |
| |
| /** |
| * Starts the digest. |
| * |
| * @return this digest object. |
| */ |
| md.start = function() { |
| // up to 56-bit message length for convenience |
| md.messageLength = 0; |
| |
| // full message length (set md.messageLength64 for backwards-compatibility) |
| md.fullMessageLength = md.messageLength64 = []; |
| var int32s = md.messageLengthSize / 4; |
| for(var i = 0; i < int32s; ++i) { |
| md.fullMessageLength.push(0); |
| } |
| _input = forge.util.createBuffer(); |
| _state = { |
| h0: 0x6A09E667, |
| h1: 0xBB67AE85, |
| h2: 0x3C6EF372, |
| h3: 0xA54FF53A, |
| h4: 0x510E527F, |
| h5: 0x9B05688C, |
| h6: 0x1F83D9AB, |
| h7: 0x5BE0CD19 |
| }; |
| return md; |
| }; |
| // start digest automatically for first time |
| md.start(); |
| |
| /** |
| * Updates the digest with the given message input. The given input can |
| * treated as raw input (no encoding will be applied) or an encoding of |
| * 'utf8' maybe given to encode the input using UTF-8. |
| * |
| * @param msg the message input to update with. |
| * @param encoding the encoding to use (default: 'raw', other: 'utf8'). |
| * |
| * @return this digest object. |
| */ |
| md.update = function(msg, encoding) { |
| if(encoding === 'utf8') { |
| msg = forge.util.encodeUtf8(msg); |
| } |
| |
| // update message length |
| var len = msg.length; |
| md.messageLength += len; |
| len = [(len / 0x100000000) >>> 0, len >>> 0]; |
| for(var i = md.fullMessageLength.length - 1; i >= 0; --i) { |
| md.fullMessageLength[i] += len[1]; |
| len[1] = len[0] + ((md.fullMessageLength[i] / 0x100000000) >>> 0); |
| md.fullMessageLength[i] = md.fullMessageLength[i] >>> 0; |
| len[0] = ((len[1] / 0x100000000) >>> 0); |
| } |
| |
| // add bytes to input buffer |
| _input.putBytes(msg); |
| |
| // process bytes |
| _update(_state, _w, _input); |
| |
| // compact input buffer every 2K or if empty |
| if(_input.read > 2048 || _input.length() === 0) { |
| _input.compact(); |
| } |
| |
| return md; |
| }; |
| |
| /** |
| * Produces the digest. |
| * |
| * @return a byte buffer containing the digest value. |
| */ |
| md.digest = function() { |
| /* Note: Here we copy the remaining bytes in the input buffer and |
| add the appropriate SHA-256 padding. Then we do the final update |
| on a copy of the state so that if the user wants to get |
| intermediate digests they can do so. */ |
| |
| /* Determine the number of bytes that must be added to the message |
| to ensure its length is congruent to 448 mod 512. In other words, |
| the data to be digested must be a multiple of 512 bits (or 128 bytes). |
| This data includes the message, some padding, and the length of the |
| message. Since the length of the message will be encoded as 8 bytes (64 |
| bits), that means that the last segment of the data must have 56 bytes |
| (448 bits) of message and padding. Therefore, the length of the message |
| plus the padding must be congruent to 448 mod 512 because |
| 512 - 128 = 448. |
| |
| In order to fill up the message length it must be filled with |
| padding that begins with 1 bit followed by all 0 bits. Padding |
| must *always* be present, so if the message length is already |
| congruent to 448 mod 512, then 512 padding bits must be added. */ |
| |
| var finalBlock = forge.util.createBuffer(); |
| finalBlock.putBytes(_input.bytes()); |
| |
| // compute remaining size to be digested (include message length size) |
| var remaining = ( |
| md.fullMessageLength[md.fullMessageLength.length - 1] + |
| md.messageLengthSize); |
| |
| // add padding for overflow blockSize - overflow |
| // _padding starts with 1 byte with first bit is set (byte value 128), then |
| // there may be up to (blockSize - 1) other pad bytes |
| var overflow = remaining & (md.blockLength - 1); |
| finalBlock.putBytes(_padding.substr(0, md.blockLength - overflow)); |
| |
| // serialize message length in bits in big-endian order; since length |
| // is stored in bytes we multiply by 8 and add carry from next int |
| var next, carry; |
| var bits = md.fullMessageLength[0] * 8; |
| for(var i = 0; i < md.fullMessageLength.length - 1; ++i) { |
| next = md.fullMessageLength[i + 1] * 8; |
| carry = (next / 0x100000000) >>> 0; |
| bits += carry; |
| finalBlock.putInt32(bits >>> 0); |
| bits = next >>> 0; |
| } |
| finalBlock.putInt32(bits); |
| |
| var s2 = { |
| h0: _state.h0, |
| h1: _state.h1, |
| h2: _state.h2, |
| h3: _state.h3, |
| h4: _state.h4, |
| h5: _state.h5, |
| h6: _state.h6, |
| h7: _state.h7 |
| }; |
| _update(s2, _w, finalBlock); |
| var rval = forge.util.createBuffer(); |
| rval.putInt32(s2.h0); |
| rval.putInt32(s2.h1); |
| rval.putInt32(s2.h2); |
| rval.putInt32(s2.h3); |
| rval.putInt32(s2.h4); |
| rval.putInt32(s2.h5); |
| rval.putInt32(s2.h6); |
| rval.putInt32(s2.h7); |
| return rval; |
| }; |
| |
| return md; |
| }; |
| |
| // sha-256 padding bytes not initialized yet |
| var _padding = null; |
| var _initialized = false; |
| |
| // table of constants |
| var _k = null; |
| |
| /** |
| * Initializes the constant tables. |
| */ |
| function _init() { |
| // create padding |
| _padding = String.fromCharCode(128); |
| _padding += forge.util.fillString(String.fromCharCode(0x00), 64); |
| |
| // create K table for SHA-256 |
| _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]; |
| |
| // now initialized |
| _initialized = true; |
| } |
| |
| /** |
| * Updates a SHA-256 state with the given byte buffer. |
| * |
| * @param s the SHA-256 state to update. |
| * @param w the array to use to store words. |
| * @param bytes the byte buffer to update with. |
| */ |
| function _update(s, w, bytes) { |
| // consume 512 bit (64 byte) chunks |
| var t1, t2, s0, s1, ch, maj, i, a, b, c, d, e, f, g, h; |
| var len = bytes.length(); |
| while(len >= 64) { |
| // the w array will be populated with sixteen 32-bit big-endian words |
| // and then extended into 64 32-bit words according to SHA-256 |
| for(i = 0; i < 16; ++i) { |
| w[i] = bytes.getInt32(); |
| } |
| for(; i < 64; ++i) { |
| // XOR word 2 words ago rot right 17, rot right 19, shft right 10 |
| t1 = w[i - 2]; |
| t1 = |
| ((t1 >>> 17) | (t1 << 15)) ^ |
| ((t1 >>> 19) | (t1 << 13)) ^ |
| (t1 >>> 10); |
| // XOR word 15 words ago rot right 7, rot right 18, shft right 3 |
| t2 = w[i - 15]; |
| t2 = |
| ((t2 >>> 7) | (t2 << 25)) ^ |
| ((t2 >>> 18) | (t2 << 14)) ^ |
| (t2 >>> 3); |
| // sum(t1, word 7 ago, t2, word 16 ago) modulo 2^32 |
| w[i] = (t1 + w[i - 7] + t2 + w[i - 16]) | 0; |
| } |
| |
| // initialize hash value for this chunk |
| a = s.h0; |
| b = s.h1; |
| c = s.h2; |
| d = s.h3; |
| e = s.h4; |
| f = s.h5; |
| g = s.h6; |
| h = s.h7; |
| |
| // round function |
| for(i = 0; i < 64; ++i) { |
| // Sum1(e) |
| s1 = |
| ((e >>> 6) | (e << 26)) ^ |
| ((e >>> 11) | (e << 21)) ^ |
| ((e >>> 25) | (e << 7)); |
| // Ch(e, f, g) (optimized the same way as SHA-1) |
| ch = g ^ (e & (f ^ g)); |
| // Sum0(a) |
| s0 = |
| ((a >>> 2) | (a << 30)) ^ |
| ((a >>> 13) | (a << 19)) ^ |
| ((a >>> 22) | (a << 10)); |
| // Maj(a, b, c) (optimized the same way as SHA-1) |
| maj = (a & b) | (c & (a ^ b)); |
| |
| // main algorithm |
| t1 = h + s1 + ch + _k[i] + w[i]; |
| t2 = s0 + maj; |
| h = g; |
| g = f; |
| f = e; |
| // `>>> 0` necessary to avoid iOS/Safari 10 optimization bug |
| // can't truncate with `| 0` |
| e = (d + t1) >>> 0; |
| d = c; |
| c = b; |
| b = a; |
| // `>>> 0` necessary to avoid iOS/Safari 10 optimization bug |
| // can't truncate with `| 0` |
| a = (t1 + t2) >>> 0; |
| } |
| |
| // update hash state |
| s.h0 = (s.h0 + a) | 0; |
| s.h1 = (s.h1 + b) | 0; |
| s.h2 = (s.h2 + c) | 0; |
| s.h3 = (s.h3 + d) | 0; |
| s.h4 = (s.h4 + e) | 0; |
| s.h5 = (s.h5 + f) | 0; |
| s.h6 = (s.h6 + g) | 0; |
| s.h7 = (s.h7 + h) | 0; |
| len -= 64; |
| } |
| } |