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// Copyright 2005 The Closure Library Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS-IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
/**
* @fileoverview SHA-1 cryptographic hash.
* Variable names follow the notation in FIPS PUB 180-3:
* http://csrc.nist.gov/publications/fips/fips180-3/fips180-3_final.pdf.
*
* Usage:
* var sha1 = new goog.crypt.sha1();
* sha1.update(bytes);
* var hash = sha1.digest();
*
*/
goog.provide('goog.crypt.Sha1');
goog.require('goog.crypt.Hash');
/**
* SHA-1 cryptographic hash constructor.
*
* The properties declared here are discussed in the above algorithm document.
* @constructor
* @extends {goog.crypt.Hash}
*/
goog.crypt.Sha1 = function() {
goog.base(this);
/**
* Holds the previous values of accumulated variables a-e in the compress_
* function.
* @type {Array.<number>}
* @private
*/
this.chain_ = [];
/**
* A buffer holding the partially computed hash result.
* @type {Array.<number>}
* @private
*/
this.buf_ = [];
/**
* An array of 80 bytes, each a part of the message to be hashed. Referred to
* as the message schedule in the docs.
* @type {Array.<number>}
* @private
*/
this.W_ = [];
/**
* Contains data needed to pad messages less than 64 bytes.
* @type {Array.<number>}
* @private
*/
this.pad_ = [];
this.pad_[0] = 128;
for (var i = 1; i < 64; ++i) {
this.pad_[i] = 0;
}
this.reset();
};
goog.inherits(goog.crypt.Sha1, goog.crypt.Hash);
/** @override */
goog.crypt.Sha1.prototype.reset = function() {
this.chain_[0] = 0x67452301;
this.chain_[1] = 0xefcdab89;
this.chain_[2] = 0x98badcfe;
this.chain_[3] = 0x10325476;
this.chain_[4] = 0xc3d2e1f0;
this.inbuf_ = 0;
this.total_ = 0;
};
/**
* Internal compress helper function.
* @param {Array.<number>} buf Buffer with the block to compress.
* @param {number=} opt_offset Offset of the block in the buffer.
* @private
*/
goog.crypt.Sha1.prototype.compress_ = function(buf, opt_offset) {
if (!opt_offset) {
opt_offset = 0;
}
var W = this.W_;
// get 16 big endian words
for (var i = opt_offset; i < opt_offset + 64; i += 4) {
var w = (buf[i] << 24) |
(buf[i + 1] << 16) |
(buf[i + 2] << 8) |
(buf[i + 3]);
W[i / 4] = w;
}
// expand to 80 words
for (var i = 16; i < 80; i++) {
var t = W[i - 3] ^ W[i - 8] ^ W[i - 14] ^ W[i - 16];
W[i] = ((t << 1) | (t >>> 31)) & 0xffffffff;
}
var a = this.chain_[0];
var b = this.chain_[1];
var c = this.chain_[2];
var d = this.chain_[3];
var e = this.chain_[4];
var f, k;
// TODO(user): Try to unroll this loop to speed up the computation.
for (var i = 0; i < 80; i++) {
if (i < 40) {
if (i < 20) {
f = d ^ (b & (c ^ d));
k = 0x5a827999;
} else {
f = b ^ c ^ d;
k = 0x6ed9eba1;
}
} else {
if (i < 60) {
f = (b & c) | (d & (b | c));
k = 0x8f1bbcdc;
} else {
f = b ^ c ^ d;
k = 0xca62c1d6;
}
}
var t = (((a << 5) | (a >>> 27)) + f + e + k + W[i]) & 0xffffffff;
e = d;
d = c;
c = ((b << 30) | (b >>> 2)) & 0xffffffff;
b = a;
a = t;
}
this.chain_[0] = (this.chain_[0] + a) & 0xffffffff;
this.chain_[1] = (this.chain_[1] + b) & 0xffffffff;
this.chain_[2] = (this.chain_[2] + c) & 0xffffffff;
this.chain_[3] = (this.chain_[3] + d) & 0xffffffff;
this.chain_[4] = (this.chain_[4] + e) & 0xffffffff;
};
/** @override */
goog.crypt.Sha1.prototype.update = function(bytes, opt_length) {
if (!goog.isDef(opt_length)) {
opt_length = bytes.length;
}
var buf = this.buf_;
var inbuf = this.inbuf_;
var n = 0;
// Strangely enough, it is faster to copy the data than to pass over the
// buffer and an offset. Copying in a loop is also as fast as array slicing.
// This was tested on Chrome 11 and Firefox 3.6. Please do not optimize
// the following without careful profiling.
if (goog.isString(bytes)) {
while (n < opt_length) {
buf[inbuf++] = bytes.charCodeAt(n++);
if (inbuf == 64) {
this.compress_(buf);
inbuf = 0;
}
}
} else {
while (n < opt_length) {
buf[inbuf++] = bytes[n++];
if (inbuf == 64) {
this.compress_(buf);
inbuf = 0;
}
}
}
this.inbuf_ = inbuf;
this.total_ += opt_length;
};
/** @override */
goog.crypt.Sha1.prototype.digest = function() {
var digest = [];
var totalBits = this.total_ * 8;
// Add pad 0x80 0x00*.
if (this.inbuf_ < 56) {
this.update(this.pad_, 56 - this.inbuf_);
} else {
this.update(this.pad_, 64 - (this.inbuf_ - 56));
}
// Add # bits.
for (var i = 63; i >= 56; i--) {
this.buf_[i] = totalBits & 255;
totalBits /= 256; // Don't use bit-shifting here!
}
this.compress_(this.buf_);
var n = 0;
for (var i = 0; i < 5; i++) {
for (var j = 24; j >= 0; j -= 8) {
digest[n++] = (this.chain_[i] >> j) & 255;
}
}
return digest;
};
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