320 lines
8.9 KiB
JavaScript
320 lines
8.9 KiB
JavaScript
/**
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* Secure Hash Algorithm with 160-bit digest (SHA-1) implementation.
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*
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* @author Dave Longley
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*
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* Copyright (c) 2010-2015 Digital Bazaar, Inc.
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*/
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var forge = require('./forge');
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require('./md');
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require('./util');
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var sha1 = module.exports = forge.sha1 = forge.sha1 || {};
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forge.md.sha1 = forge.md.algorithms.sha1 = sha1;
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/**
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* Creates a SHA-1 message digest object.
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*
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* @return a message digest object.
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*/
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sha1.create = function() {
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// do initialization as necessary
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if(!_initialized) {
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_init();
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}
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// SHA-1 state contains five 32-bit integers
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var _state = null;
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// input buffer
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var _input = forge.util.createBuffer();
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// used for word storage
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var _w = new Array(80);
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// message digest object
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var md = {
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algorithm: 'sha1',
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blockLength: 64,
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digestLength: 20,
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// 56-bit length of message so far (does not including padding)
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messageLength: 0,
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// true message length
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fullMessageLength: null,
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// size of message length in bytes
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messageLengthSize: 8
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};
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/**
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* Starts the digest.
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*
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* @return this digest object.
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*/
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md.start = function() {
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// up to 56-bit message length for convenience
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md.messageLength = 0;
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// full message length (set md.messageLength64 for backwards-compatibility)
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md.fullMessageLength = md.messageLength64 = [];
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var int32s = md.messageLengthSize / 4;
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for(var i = 0; i < int32s; ++i) {
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md.fullMessageLength.push(0);
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}
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_input = forge.util.createBuffer();
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_state = {
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h0: 0x67452301,
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h1: 0xEFCDAB89,
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h2: 0x98BADCFE,
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h3: 0x10325476,
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h4: 0xC3D2E1F0
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};
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return md;
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};
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// start digest automatically for first time
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md.start();
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/**
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* Updates the digest with the given message input. The given input can
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* treated as raw input (no encoding will be applied) or an encoding of
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* 'utf8' maybe given to encode the input using UTF-8.
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*
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* @param msg the message input to update with.
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* @param encoding the encoding to use (default: 'raw', other: 'utf8').
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*
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* @return this digest object.
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*/
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md.update = function(msg, encoding) {
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if(encoding === 'utf8') {
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msg = forge.util.encodeUtf8(msg);
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}
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// update message length
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var len = msg.length;
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md.messageLength += len;
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len = [(len / 0x100000000) >>> 0, len >>> 0];
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for(var i = md.fullMessageLength.length - 1; i >= 0; --i) {
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md.fullMessageLength[i] += len[1];
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len[1] = len[0] + ((md.fullMessageLength[i] / 0x100000000) >>> 0);
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md.fullMessageLength[i] = md.fullMessageLength[i] >>> 0;
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len[0] = ((len[1] / 0x100000000) >>> 0);
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}
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// add bytes to input buffer
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_input.putBytes(msg);
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// process bytes
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_update(_state, _w, _input);
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// compact input buffer every 2K or if empty
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if(_input.read > 2048 || _input.length() === 0) {
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_input.compact();
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}
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return md;
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};
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/**
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* Produces the digest.
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*
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* @return a byte buffer containing the digest value.
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*/
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md.digest = function() {
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/* Note: Here we copy the remaining bytes in the input buffer and
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add the appropriate SHA-1 padding. Then we do the final update
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on a copy of the state so that if the user wants to get
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intermediate digests they can do so. */
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/* Determine the number of bytes that must be added to the message
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to ensure its length is congruent to 448 mod 512. In other words,
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the data to be digested must be a multiple of 512 bits (or 128 bytes).
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This data includes the message, some padding, and the length of the
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message. Since the length of the message will be encoded as 8 bytes (64
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bits), that means that the last segment of the data must have 56 bytes
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(448 bits) of message and padding. Therefore, the length of the message
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plus the padding must be congruent to 448 mod 512 because
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512 - 128 = 448.
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In order to fill up the message length it must be filled with
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padding that begins with 1 bit followed by all 0 bits. Padding
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must *always* be present, so if the message length is already
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congruent to 448 mod 512, then 512 padding bits must be added. */
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var finalBlock = forge.util.createBuffer();
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finalBlock.putBytes(_input.bytes());
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// compute remaining size to be digested (include message length size)
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var remaining = (
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md.fullMessageLength[md.fullMessageLength.length - 1] +
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md.messageLengthSize);
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// add padding for overflow blockSize - overflow
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// _padding starts with 1 byte with first bit is set (byte value 128), then
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// there may be up to (blockSize - 1) other pad bytes
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var overflow = remaining & (md.blockLength - 1);
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finalBlock.putBytes(_padding.substr(0, md.blockLength - overflow));
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// serialize message length in bits in big-endian order; since length
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// is stored in bytes we multiply by 8 and add carry from next int
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var next, carry;
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var bits = md.fullMessageLength[0] * 8;
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for(var i = 0; i < md.fullMessageLength.length - 1; ++i) {
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next = md.fullMessageLength[i + 1] * 8;
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carry = (next / 0x100000000) >>> 0;
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bits += carry;
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finalBlock.putInt32(bits >>> 0);
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bits = next >>> 0;
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}
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finalBlock.putInt32(bits);
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var s2 = {
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h0: _state.h0,
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h1: _state.h1,
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h2: _state.h2,
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h3: _state.h3,
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h4: _state.h4
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};
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_update(s2, _w, finalBlock);
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var rval = forge.util.createBuffer();
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rval.putInt32(s2.h0);
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rval.putInt32(s2.h1);
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rval.putInt32(s2.h2);
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rval.putInt32(s2.h3);
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rval.putInt32(s2.h4);
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return rval;
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};
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return md;
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};
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// sha-1 padding bytes not initialized yet
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var _padding = null;
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var _initialized = false;
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/**
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* Initializes the constant tables.
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*/
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function _init() {
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// create padding
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_padding = String.fromCharCode(128);
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_padding += forge.util.fillString(String.fromCharCode(0x00), 64);
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// now initialized
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_initialized = true;
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}
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/**
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* Updates a SHA-1 state with the given byte buffer.
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*
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* @param s the SHA-1 state to update.
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* @param w the array to use to store words.
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* @param bytes the byte buffer to update with.
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*/
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function _update(s, w, bytes) {
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// consume 512 bit (64 byte) chunks
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var t, a, b, c, d, e, f, i;
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var len = bytes.length();
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while(len >= 64) {
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// the w array will be populated with sixteen 32-bit big-endian words
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// and then extended into 80 32-bit words according to SHA-1 algorithm
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// and for 32-79 using Max Locktyukhin's optimization
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// initialize hash value for this chunk
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a = s.h0;
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b = s.h1;
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c = s.h2;
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d = s.h3;
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e = s.h4;
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// round 1
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for(i = 0; i < 16; ++i) {
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t = bytes.getInt32();
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w[i] = t;
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f = d ^ (b & (c ^ d));
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t = ((a << 5) | (a >>> 27)) + f + e + 0x5A827999 + t;
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e = d;
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d = c;
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// `>>> 0` necessary to avoid iOS/Safari 10 optimization bug
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c = ((b << 30) | (b >>> 2)) >>> 0;
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b = a;
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a = t;
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}
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for(; i < 20; ++i) {
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t = (w[i - 3] ^ w[i - 8] ^ w[i - 14] ^ w[i - 16]);
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t = (t << 1) | (t >>> 31);
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w[i] = t;
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f = d ^ (b & (c ^ d));
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t = ((a << 5) | (a >>> 27)) + f + e + 0x5A827999 + t;
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e = d;
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d = c;
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// `>>> 0` necessary to avoid iOS/Safari 10 optimization bug
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c = ((b << 30) | (b >>> 2)) >>> 0;
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b = a;
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a = t;
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}
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// round 2
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for(; i < 32; ++i) {
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t = (w[i - 3] ^ w[i - 8] ^ w[i - 14] ^ w[i - 16]);
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t = (t << 1) | (t >>> 31);
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w[i] = t;
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f = b ^ c ^ d;
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t = ((a << 5) | (a >>> 27)) + f + e + 0x6ED9EBA1 + t;
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e = d;
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d = c;
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// `>>> 0` necessary to avoid iOS/Safari 10 optimization bug
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c = ((b << 30) | (b >>> 2)) >>> 0;
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b = a;
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a = t;
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}
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for(; i < 40; ++i) {
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t = (w[i - 6] ^ w[i - 16] ^ w[i - 28] ^ w[i - 32]);
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t = (t << 2) | (t >>> 30);
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w[i] = t;
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f = b ^ c ^ d;
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t = ((a << 5) | (a >>> 27)) + f + e + 0x6ED9EBA1 + t;
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e = d;
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d = c;
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// `>>> 0` necessary to avoid iOS/Safari 10 optimization bug
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c = ((b << 30) | (b >>> 2)) >>> 0;
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b = a;
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a = t;
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}
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// round 3
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for(; i < 60; ++i) {
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t = (w[i - 6] ^ w[i - 16] ^ w[i - 28] ^ w[i - 32]);
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t = (t << 2) | (t >>> 30);
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w[i] = t;
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f = (b & c) | (d & (b ^ c));
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t = ((a << 5) | (a >>> 27)) + f + e + 0x8F1BBCDC + t;
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e = d;
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d = c;
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// `>>> 0` necessary to avoid iOS/Safari 10 optimization bug
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c = ((b << 30) | (b >>> 2)) >>> 0;
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b = a;
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a = t;
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}
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// round 4
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for(; i < 80; ++i) {
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t = (w[i - 6] ^ w[i - 16] ^ w[i - 28] ^ w[i - 32]);
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t = (t << 2) | (t >>> 30);
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w[i] = t;
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f = b ^ c ^ d;
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t = ((a << 5) | (a >>> 27)) + f + e + 0xCA62C1D6 + t;
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e = d;
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d = c;
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// `>>> 0` necessary to avoid iOS/Safari 10 optimization bug
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c = ((b << 30) | (b >>> 2)) >>> 0;
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b = a;
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a = t;
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}
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// update hash state
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s.h0 = (s.h0 + a) | 0;
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s.h1 = (s.h1 + b) | 0;
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s.h2 = (s.h2 + c) | 0;
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s.h3 = (s.h3 + d) | 0;
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s.h4 = (s.h4 + e) | 0;
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len -= 64;
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}
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}
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