Byte order fix for MD5

MD5.as

/*
  Copyright (c) 2008, Adobe Systems Incorporated
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  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
  IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR 
  CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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*/

package com.adobe.crypto {
	
	import com.adobe.utils.IntUtil;
	import flash.utils.ByteArray;	
	import flash.utils.Endian;

	/**
	 * The MD5 Message-Digest Algorithm
	 *
	 * Implementation based on algorithm description at 
	 * http://www.faqs.org/rfcs/rfc1321.html
	 */
	public class MD5 {
		
		public static var digest:ByteArray;
		/**
		 * Performs the MD5 hash algorithm on a string.
		 *
		 * @param s The string to hash
		 * @return A string containing the hash value of s
		 * @langversion ActionScript 3.0
		 * @playerversion Flash 8.5
		 * @tiptext
		 */
		 
		public static function hash(s:String) :String{
			//Convert to byteArray and send through hashBinary function
			// so as to only have complex code in one location
			var ba:ByteArray = new ByteArray();
			ba.writeUTFBytes(s);	
			return hashBinary(ba);
		}
		
		public static function hashBytes(s:ByteArray) :String{	
			return hashBinary(s);
		}
		
		/**
		 * Performs the MD5 hash algorithm on a ByteArray.
		 *
		 * @param s The string to hash
		 * @return A string containing the hash value of s
		 * @langversion ActionScript 3.0
		 * @playerversion Flash 8.5
		 * @tiptext
		 */	 
		public static function hashBinary( s:ByteArray ):String {
			// initialize the md buffers
			var a:int = 1732584193;
			var b:int = -271733879;
			var c:int = -1732584194;
			var d:int = 271733878;
			
			// variables to store previous values
			var aa:int;
			var bb:int;
			var cc:int;
			var dd:int;
			
			// create the blocks from the string and
			// save the length as a local var to reduce
			// lookup in the loop below
			var x:Array = createBlocks( s );
			var len:int = x.length;
			
			// loop over all of the blocks
			for ( var i:int = 0; i < len; i += 16) {
				// save previous values
				aa = a;
				bb = b;
				cc = c;
				dd = d;				
				
				// Round 1
				a = ff( a, b, c, d, x[int(i+ 0)],  7, -680876936 ); 	// 1
				d = ff( d, a, b, c, x[int(i+ 1)], 12, -389564586 );	// 2
				c = ff( c, d, a, b, x[int(i+ 2)], 17, 606105819 ); 	// 3
				b = ff( b, c, d, a, x[int(i+ 3)], 22, -1044525330 );	// 4
				a = ff( a, b, c, d, x[int(i+ 4)],  7, -176418897 ); 	// 5
				d = ff( d, a, b, c, x[int(i+ 5)], 12, 1200080426 ); 	// 6
				c = ff( c, d, a, b, x[int(i+ 6)], 17, -1473231341 );	// 7
				b = ff( b, c, d, a, x[int(i+ 7)], 22, -45705983 ); 	// 8
				a = ff( a, b, c, d, x[int(i+ 8)],  7, 1770035416 ); 	// 9
				d = ff( d, a, b, c, x[int(i+ 9)], 12, -1958414417 );	// 10
				c = ff( c, d, a, b, x[int(i+10)], 17, -42063 ); 		// 11
				b = ff( b, c, d, a, x[int(i+11)], 22, -1990404162 );	// 12
				a = ff( a, b, c, d, x[int(i+12)],  7, 1804603682 ); 	// 13
				d = ff( d, a, b, c, x[int(i+13)], 12, -40341101 ); 	// 14
				c = ff( c, d, a, b, x[int(i+14)], 17, -1502002290 );	// 15
				b = ff( b, c, d, a, x[int(i+15)], 22, 1236535329 ); 	// 16
				
				// Round 2
				a = gg( a, b, c, d, x[int(i+ 1)],  5, -165796510 ); 	// 17
				d = gg( d, a, b, c, x[int(i+ 6)],  9, -1069501632 );	// 18
				c = gg( c, d, a, b, x[int(i+11)], 14, 643717713 ); 	// 19
				b = gg( b, c, d, a, x[int(i+ 0)], 20, -373897302 ); 	// 20
				a = gg( a, b, c, d, x[int(i+ 5)],  5, -701558691 ); 	// 21
				d = gg( d, a, b, c, x[int(i+10)],  9, 38016083 ); 	// 22
				c = gg( c, d, a, b, x[int(i+15)], 14, -660478335 ); 	// 23
				b = gg( b, c, d, a, x[int(i+ 4)], 20, -405537848 ); 	// 24
				a = gg( a, b, c, d, x[int(i+ 9)],  5, 568446438 ); 	// 25
				d = gg( d, a, b, c, x[int(i+14)],  9, -1019803690 );	// 26
				c = gg( c, d, a, b, x[int(i+ 3)], 14, -187363961 ); 	// 27
				b = gg( b, c, d, a, x[int(i+ 8)], 20, 1163531501 ); 	// 28
				a = gg( a, b, c, d, x[int(i+13)],  5, -1444681467 );	// 29
				d = gg( d, a, b, c, x[int(i+ 2)],  9, -51403784 ); 	// 30
				c = gg( c, d, a, b, x[int(i+ 7)], 14, 1735328473 ); 	// 31
				b = gg( b, c, d, a, x[int(i+12)], 20, -1926607734 );	// 32
				
				// Round 3
				a = hh( a, b, c, d, x[int(i+ 5)],  4, -378558 ); 	// 33
				d = hh( d, a, b, c, x[int(i+ 8)], 11, -2022574463 );	// 34
				c = hh( c, d, a, b, x[int(i+11)], 16, 1839030562 ); 	// 35
				b = hh( b, c, d, a, x[int(i+14)], 23, -35309556 ); 	// 36
				a = hh( a, b, c, d, x[int(i+ 1)],  4, -1530992060 );	// 37
				d = hh( d, a, b, c, x[int(i+ 4)], 11, 1272893353 ); 	// 38
				c = hh( c, d, a, b, x[int(i+ 7)], 16, -155497632 ); 	// 39
				b = hh( b, c, d, a, x[int(i+10)], 23, -1094730640 );	// 40
				a = hh( a, b, c, d, x[int(i+13)],  4, 681279174 ); 	// 41
				d = hh( d, a, b, c, x[int(i+ 0)], 11, -358537222 ); 	// 42
				c = hh( c, d, a, b, x[int(i+ 3)], 16, -722521979 ); 	// 43
				b = hh( b, c, d, a, x[int(i+ 6)], 23, 76029189 ); 	// 44
				a = hh( a, b, c, d, x[int(i+ 9)],  4, -640364487 ); 	// 45
				d = hh( d, a, b, c, x[int(i+12)], 11, -421815835 ); 	// 46
				c = hh( c, d, a, b, x[int(i+15)], 16, 530742520 ); 	// 47
				b = hh( b, c, d, a, x[int(i+ 2)], 23, -995338651 ); 	// 48
				
				// Round 4
				a = ii( a, b, c, d, x[int(i+ 0)],  6, -198630844 ); 	// 49
				d = ii( d, a, b, c, x[int(i+ 7)], 10, 1126891415 ); 	// 50
				c = ii( c, d, a, b, x[int(i+14)], 15, -1416354905 );	// 51
				b = ii( b, c, d, a, x[int(i+ 5)], 21, -57434055 ); 	// 52
				a = ii( a, b, c, d, x[int(i+12)],  6, 1700485571 ); 	// 53
				d = ii( d, a, b, c, x[int(i+ 3)], 10, -1894986606 );	// 54
				c = ii( c, d, a, b, x[int(i+10)], 15, -1051523 ); 	// 55
				b = ii( b, c, d, a, x[int(i+ 1)], 21, -2054922799 );	// 56
				a = ii( a, b, c, d, x[int(i+ 8)],  6, 1873313359 ); 	// 57
				d = ii( d, a, b, c, x[int(i+15)], 10, -30611744 ); 	// 58
				c = ii( c, d, a, b, x[int(i+ 6)], 15, -1560198380 );	// 59
				b = ii( b, c, d, a, x[int(i+13)], 21, 1309151649 ); 	// 60
				a = ii( a, b, c, d, x[int(i+ 4)],  6, -145523070 ); 	// 61
				d = ii( d, a, b, c, x[int(i+11)], 10, -1120210379 );	// 62
				c = ii( c, d, a, b, x[int(i+ 2)], 15, 718787259 ); 	// 63
				b = ii( b, c, d, a, x[int(i+ 9)], 21, -343485551 ); 	// 64

				a += aa;
				b += bb;
				c += cc;
				d += dd;
			}
			digest = new ByteArray()
			digest.endian = Endian.LITTLE_ENDIAN
			digest.writeInt(a);
			digest.writeInt(b);
			digest.writeInt(c);
			digest.writeInt(d);
			digest.position = 0;
			// Finish up by concatening the buffers with their hex output
			return IntUtil.toHex( a ) + IntUtil.toHex( b ) + IntUtil.toHex( c ) + IntUtil.toHex( d );
		}
		
		/**
		 * Auxiliary function f as defined in RFC
		 */
		private static function f( x:int, y:int, z:int ):int {
			return ( x & y ) | ( (~x) & z );
		}
		
		/**
		 * Auxiliary function g as defined in RFC
		 */
		private static function g( x:int, y:int, z:int ):int {
			return ( x & z ) | ( y & (~z) );
		}
		
		/**
		 * Auxiliary function h as defined in RFC
		 */
		private static function h( x:int, y:int, z:int ):int {
			return x ^ y ^ z;
		}
		
		/**
		 * Auxiliary function i as defined in RFC
		 */
		private static function i( x:int, y:int, z:int ):int {
			return y ^ ( x | (~z) );
		}
		
		/**
		 * A generic transformation function.  The logic of ff, gg, hh, and
		 * ii are all the same, minus the function used, so pull that logic
		 * out and simplify the method bodies for the transoformation functions.
		 */
		private static function transform( func:Function, a:int, b:int, c:int, d:int, x:int, s:int, t:int):int {
			var tmp:int = a + int( func( b, c, d ) ) + x + t;
			return IntUtil.rol( tmp, s ) +  b;
		}
		
		/**
		 * ff transformation function
		 */
		private static function ff ( a:int, b:int, c:int, d:int, x:int, s:int, t:int ):int {
			return transform( f, a, b, c, d, x, s, t );
		}
		
		/**
		 * gg transformation function
		 */
		private static function gg ( a:int, b:int, c:int, d:int, x:int, s:int, t:int ):int {
			return transform( g, a, b, c, d, x, s, t );
		}
		
		/**
		 * hh transformation function
		 */
		private static function hh ( a:int, b:int, c:int, d:int, x:int, s:int, t:int ):int {
			return transform( h, a, b, c, d, x, s, t );
		}
		
		/**
		 * ii transformation function
		 */
		private static function ii ( a:int, b:int, c:int, d:int, x:int, s:int, t:int ):int {
			return transform( i, a, b, c, d, x, s, t );
		}
		
		/**
		 * Converts a string to a sequence of 16-word blocks
		 * that we'll do the processing on.  Appends padding
		 * and length in the process.
		 *
		 * @param s The string to split into blocks
		 * @return An array containing the blocks that s was
		 *			split into.
		 */
		private static function createBlocks( s:ByteArray ):Array {
			var blocks:Array = new Array();
			var len:int = s.length * 8;
			var mask:int = 0xFF; // ignore hi byte of characters > 0xFF
			for( var i:int = 0; i < len; i += 8 ) {
				blocks[ int(i >> 5) ] |= ( s[ i / 8 ] & mask ) << ( i % 32 );
			}
			
			// append padding and length
			blocks[ int(len >> 5) ] |= 0x80 << ( len % 32 );
			blocks[ int(( ( ( len + 64 ) >>> 9 ) << 4 ) + 14) ] = len;
			return blocks;
		}
		
	}
}