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							290 lines
						
					
					
						
							7.8 KiB
						
					
					
				
			
		
		
	
	
							290 lines
						
					
					
						
							7.8 KiB
						
					
					
				| /**
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|  * Message Digest Algorithm 5 with 128-bit digest (MD5) implementation.
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|  *
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|  * @author Dave Longley
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|  *
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|  * Copyright (c) 2010-2014 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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| 
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| var md5 = module.exports = forge.md5 = forge.md5 || {};
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| forge.md.md5 = forge.md.algorithms.md5 = md5;
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| 
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| /**
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|  * Creates an MD5 message digest object.
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|  *
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|  * @return a message digest object.
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|  */
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| md5.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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| 
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|   // MD5 state contains four 32-bit integers
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|   var _state = null;
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| 
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|   // input buffer
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|   var _input = forge.util.createBuffer();
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| 
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|   // used for word storage
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|   var _w = new Array(16);
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| 
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|   // message digest object
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|   var md = {
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|     algorithm: 'md5',
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|     blockLength: 64,
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|     digestLength: 16,
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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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|   /**
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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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| 
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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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|     };
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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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|   /**
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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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| 
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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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| 
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|     // add bytes to input buffer
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|     _input.putBytes(msg);
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| 
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|     // process bytes
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|     _update(_state, _w, _input);
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| 
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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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| 
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|     return md;
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|   };
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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 MD5 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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| 
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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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| 
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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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| 
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|     var finalBlock = forge.util.createBuffer();
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|     finalBlock.putBytes(_input.bytes());
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| 
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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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| 
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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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| 
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|     // serialize message length in bits in little-endian order; since length
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|     // is stored in bytes we multiply by 8 and add carry
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|     var bits, carry = 0;
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|     for(var i = md.fullMessageLength.length - 1; i >= 0; --i) {
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|       bits = md.fullMessageLength[i] * 8 + carry;
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|       carry = (bits / 0x100000000) >>> 0;
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|       finalBlock.putInt32Le(bits >>> 0);
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|     }
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| 
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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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|     };
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|     _update(s2, _w, finalBlock);
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|     var rval = forge.util.createBuffer();
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|     rval.putInt32Le(s2.h0);
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|     rval.putInt32Le(s2.h1);
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|     rval.putInt32Le(s2.h2);
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|     rval.putInt32Le(s2.h3);
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|     return rval;
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|   };
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| 
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|   return md;
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| };
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| 
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| // padding, constant tables for calculating md5
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| var _padding = null;
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| var _g = null;
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| var _r = null;
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| var _k = null;
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| var _initialized = false;
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| 
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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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| 
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|   // g values
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|   _g = [
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|     0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
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|     1, 6, 11, 0, 5, 10, 15, 4, 9, 14, 3, 8, 13, 2, 7, 12,
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|     5, 8, 11, 14, 1, 4, 7, 10, 13, 0, 3, 6, 9, 12, 15, 2,
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|     0, 7, 14, 5, 12, 3, 10, 1, 8, 15, 6, 13, 4, 11, 2, 9];
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| 
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|   // rounds table
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|   _r = [
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|     7, 12, 17, 22,  7, 12, 17, 22,  7, 12, 17, 22,  7, 12, 17, 22,
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|     5,  9, 14, 20,  5,  9, 14, 20,  5,  9, 14, 20,  5,  9, 14, 20,
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|     4, 11, 16, 23,  4, 11, 16, 23,  4, 11, 16, 23,  4, 11, 16, 23,
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|     6, 10, 15, 21,  6, 10, 15, 21,  6, 10, 15, 21,  6, 10, 15, 21];
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| 
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|   // get the result of abs(sin(i + 1)) as a 32-bit integer
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|   _k = new Array(64);
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|   for(var i = 0; i < 64; ++i) {
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|     _k[i] = Math.floor(Math.abs(Math.sin(i + 1)) * 0x100000000);
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|   }
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| 
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|   // now initialized
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|   _initialized = true;
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| }
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| 
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| /**
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|  * Updates an MD5 state with the given byte buffer.
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|  *
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|  * @param s the MD5 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, f, r, i;
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|   var len = bytes.length();
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|   while(len >= 64) {
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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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| 
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|     // round 1
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|     for(i = 0; i < 16; ++i) {
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|       w[i] = bytes.getInt32Le();
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|       f = d ^ (b & (c ^ d));
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|       t = (a + f + _k[i] + w[i]);
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|       r = _r[i];
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|       a = d;
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|       d = c;
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|       c = b;
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|       b += (t << r) | (t >>> (32 - r));
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|     }
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|     // round 2
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|     for(; i < 32; ++i) {
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|       f = c ^ (d & (b ^ c));
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|       t = (a + f + _k[i] + w[_g[i]]);
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|       r = _r[i];
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|       a = d;
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|       d = c;
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|       c = b;
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|       b += (t << r) | (t >>> (32 - r));
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|     }
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|     // round 3
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|     for(; i < 48; ++i) {
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|       f = b ^ c ^ d;
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|       t = (a + f + _k[i] + w[_g[i]]);
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|       r = _r[i];
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|       a = d;
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|       d = c;
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|       c = b;
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|       b += (t << r) | (t >>> (32 - r));
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|     }
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|     // round 4
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|     for(; i < 64; ++i) {
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|       f = c ^ (b | ~d);
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|       t = (a + f + _k[i] + w[_g[i]]);
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|       r = _r[i];
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|       a = d;
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|       d = c;
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|       c = b;
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|       b += (t << r) | (t >>> (32 - r));
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|     }
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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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| 
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|     len -= 64;
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|   }
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| }
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