250 lines
7.4 KiB
JavaScript
250 lines
7.4 KiB
JavaScript
/*
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* A JavaScript implementation of the SHA256 hash function.
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*
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* FILE: sha256.js
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* VERSION: 0.8
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* AUTHOR: Christoph Bichlmeier <informatik@zombiearena.de>
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*
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* NOTE: This version is not tested thoroughly!
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*
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* Copyright (c) 2003, Christoph Bichlmeier
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* ======================================================================
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHORS ''AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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/* SHA256 logical functions */
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function rotateRight(n,x) {
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return ((x >>> n) | (x << (32 - n)));
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}
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function choice(x,y,z) {
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return ((x & y) ^ (~x & z));
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}
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function majority(x,y,z) {
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return ((x & y) ^ (x & z) ^ (y & z));
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}
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function sha256_Sigma0(x) {
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return (rotateRight(2, x) ^ rotateRight(13, x) ^ rotateRight(22, x));
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}
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function sha256_Sigma1(x) {
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return (rotateRight(6, x) ^ rotateRight(11, x) ^ rotateRight(25, x));
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}
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function sha256_sigma0(x) {
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return (rotateRight(7, x) ^ rotateRight(18, x) ^ (x >>> 3));
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}
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function sha256_sigma1(x) {
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return (rotateRight(17, x) ^ rotateRight(19, x) ^ (x >>> 10));
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}
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function sha256_expand(W, j) {
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return (W[j&0x0f] += sha256_sigma1(W[(j+14)&0x0f]) + W[(j+9)&0x0f] +
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sha256_sigma0(W[(j+1)&0x0f]));
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}
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/* Hash constant words K: */
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var K256 = new Array(
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0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
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0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
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0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
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0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
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0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
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0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
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0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
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0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
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0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
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0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
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0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
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0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
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0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
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0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
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0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
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0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
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);
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/* global arrays */
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var ihash, count, buffer;
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var sha256_hex_digits = "0123456789abcdef";
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/* Add 32-bit integers with 16-bit operations (bug in some JS-interpreters:
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overflow) */
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function safe_add(x, y)
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{
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var lsw = (x & 0xffff) + (y & 0xffff);
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var msw = (x >> 16) + (y >> 16) + (lsw >> 16);
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return (msw << 16) | (lsw & 0xffff);
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}
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/* Initialise the SHA256 computation */
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function sha256_init() {
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ihash = new Array(8);
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count = new Array(2);
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buffer = new Array(64);
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count[0] = count[1] = 0;
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ihash[0] = 0x6a09e667;
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ihash[1] = 0xbb67ae85;
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ihash[2] = 0x3c6ef372;
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ihash[3] = 0xa54ff53a;
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ihash[4] = 0x510e527f;
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ihash[5] = 0x9b05688c;
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ihash[6] = 0x1f83d9ab;
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ihash[7] = 0x5be0cd19;
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}
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/* Transform a 512-bit message block */
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function sha256_transform() {
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var a, b, c, d, e, f, g, h, T1, T2;
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var W = new Array(16);
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/* Initialize registers with the previous intermediate value */
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a = ihash[0];
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b = ihash[1];
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c = ihash[2];
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d = ihash[3];
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e = ihash[4];
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f = ihash[5];
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g = ihash[6];
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h = ihash[7];
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/* make 32-bit words */
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for(var i=0; i<16; i++)
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W[i] = ((buffer[(i<<2)+3]) | (buffer[(i<<2)+2] << 8) | (buffer[(i<<2)+1]
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<< 16) | (buffer[i<<2] << 24));
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for(var j=0; j<64; j++) {
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T1 = h + sha256_Sigma1(e) + choice(e, f, g) + K256[j];
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if(j < 16) T1 += W[j];
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else T1 += sha256_expand(W, j);
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T2 = sha256_Sigma0(a) + majority(a, b, c);
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h = g;
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g = f;
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f = e;
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e = safe_add(d, T1);
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d = c;
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c = b;
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b = a;
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a = safe_add(T1, T2);
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}
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/* Compute the current intermediate hash value */
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ihash[0] += a;
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ihash[1] += b;
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ihash[2] += c;
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ihash[3] += d;
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ihash[4] += e;
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ihash[5] += f;
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ihash[6] += g;
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ihash[7] += h;
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}
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/* Read the next chunk of data and update the SHA256 computation */
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function sha256_update(data, inputLen) {
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var i, index, curpos = 0;
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/* Compute number of bytes mod 64 */
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index = ((count[0] >> 3) & 0x3f);
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var remainder = (inputLen & 0x3f);
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/* Update number of bits */
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if ((count[0] += (inputLen << 3)) < (inputLen << 3)) count[1]++;
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count[1] += (inputLen >> 29);
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/* Transform as many times as possible */
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for(i=0; i+63<inputLen; i+=64) {
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for(var j=index; j<64; j++)
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buffer[j] = data.charCodeAt(curpos++);
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sha256_transform();
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index = 0;
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}
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/* Buffer remaining input */
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for(var j=0; j<remainder; j++)
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buffer[j] = data.charCodeAt(curpos++);
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}
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/* Finish the computation by operations such as padding */
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function sha256_final() {
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var index = ((count[0] >> 3) & 0x3f);
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buffer[index++] = 0x80;
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if(index <= 56) {
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for(var i=index; i<56; i++)
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buffer[i] = 0;
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} else {
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for(var i=index; i<64; i++)
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buffer[i] = 0;
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sha256_transform();
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for(var i=0; i<56; i++)
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buffer[i] = 0;
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}
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buffer[56] = (count[1] >>> 24) & 0xff;
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buffer[57] = (count[1] >>> 16) & 0xff;
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buffer[58] = (count[1] >>> 8) & 0xff;
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buffer[59] = count[1] & 0xff;
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buffer[60] = (count[0] >>> 24) & 0xff;
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buffer[61] = (count[0] >>> 16) & 0xff;
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buffer[62] = (count[0] >>> 8) & 0xff;
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buffer[63] = count[0] & 0xff;
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sha256_transform();
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}
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/* Split the internal hash values into an array of bytes */
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function sha256_encode_bytes() {
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var j=0;
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var output = new Array(32);
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for(var i=0; i<8; i++) {
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output[j++] = ((ihash[i] >>> 24) & 0xff);
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output[j++] = ((ihash[i] >>> 16) & 0xff);
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output[j++] = ((ihash[i] >>> 8) & 0xff);
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output[j++] = (ihash[i] & 0xff);
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}
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return output;
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}
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/* Get the internal hash as a hex string */
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function sha256_encode_hex() {
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var output = new String();
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for(var i=0; i<8; i++) {
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for(var j=28; j>=0; j-=4)
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output += sha256_hex_digits.charAt((ihash[i] >>> j) & 0x0f);
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}
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return output;
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}
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/* Main function: returns a hex string representing the SHA256 value of the
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given data */
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function sha256_digest(data) {
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sha256_init();
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sha256_update(data, data.length);
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sha256_final();
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return sha256_encode_hex();
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}
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/* test if the JS-interpreter is working properly */
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function sha256_self_test()
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{
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return sha256_digest("message digest") ==
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"f7846f55cf23e14eebeab5b4e1550cad5b509e3348fbc4efa3a1413d393cb650";
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}
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module.exports = {sha256_digest} |