package com.twmacinta.util;/** * Fast implementation of RSA's MD5 hash generator in Java JDK Beta-2 or higher. * <p> * Originally written by Santeri Paavolainen, Helsinki Finland 1996.<br> * (c) Santeri Paavolainen, Helsinki Finland 1996<br> * Many changes Copyright (c) 2002 - 2005 Timothy W Macinta<br> * <p> * This library is free software; you can redistribute it and/or modify it under * the terms of the GNU Library General Public License as published by the Free * Software Foundation; either version 2.1 of the License, or (at your option) * any later version. * <p> * This library is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS * FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more * details. * <p> * You should have received a copy of the GNU Library General Public License * along with this library; if not, write to the Free Software Foundation, Inc., * 675 Mass Ave, Cambridge, MA 02139, USA. * <p> * See http://www.twmacinta.com/myjava/fast_md5.php for more information on this * file and the related files. * <p> * This was originally a rather straight re-implementation of the reference * implementation given in RFC1321 by RSA. It passes the MD5 test suite as * defined in RFC1321. * <p> * Many optimizations made by Timothy W Macinta. Reduced time to checksum a test * file in Java alone to roughly half the time taken compared with * java.security.MessageDigest (within an intepretter). Also added an optional * native method to reduce the time even further. See * http://www.twmacinta.com/myjava/fast_md5.php for further information on the * time improvements achieved. * <p> * Some bug fixes also made by Timothy W Macinta. * <p> * Please note: I (Timothy Macinta) have put this code in the com.twmacinta.util * package only because it came without a package. I was not the the original * author of the code, although I did optimize it (substantially) and fix some * bugs. * <p> * This Java class has been derived from the RSA Data Security, Inc. MD5 * Message-Digest Algorithm and its reference implementation. * <p> * This class will attempt to use a native method to quickly compute checksums * when the appropriate native library is available. On Linux, this library * should be named "MD5.so" and on Windows it should be named "MD5.dll". The * code will attempt to locate the library in the following locations in the * order given: *  * <ol> * <li>The path specified by the system property * "com.twmacinta.util.MD5.NATIVE_LIB_FILE" (be sure to include "MD5.so" or * "MD5.dll" as appropriate at the end of the path). * <li>A platform specific directory beneath the "lib/arch/" directory. On * Linux for x86, this is "lib/arch/linux_x86/". On Windows for x86, this is * "lib/arch/win32_x86/". * <li>Within the "lib/" directory. * <li>Within the current directory. * </ol> *  * <p> * If the library is not found, the code will fall back to the default (slower) * Java code. * <p> * As a side effect of having the code search for the native library, * SecurityExceptions might be thrown on JVMs that have a restrictive * SecurityManager. The initialization code attempts to silently discard these * exceptions and continue, but many SecurityManagers will attempt to notify the * user directly of all SecurityExceptions thrown. Consequently, the code has * provisions for skipping the search for the native library. Any of these * provisions may be used to skip the search as long as they are performed * <i>before</i> the first instance of a com.twmacinta.util.MD5 object is * constructed (note that the convenience stream objects will implicitly create * an MD5 object). * <p> * The first option is to set the system property * "com.twmacinta.util.MD5.NO_NATIVE_LIB" to "true" or "1". Unfortunately, * SecurityManagers may also choose to disallow system property setting, so this * won't be of use in all cases. * <p> * The second option is to call com.twmacinta.util.MD5.initNativeLibrary(true) * before any MD5 objects are constructed. *  * @author Santeri Paavolainen <sjpaavol@cc.helsinki.fi> * @author Timothy W Macinta (twm@alum.mit.edu) (optimizations and bug fixes) */public class MD5 {	private static final char[]	HEX_CHARS	= { 		'0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f' 	};		private MD5State	state;	private MD5State	finals;	private static final byte	padding[]	= { (byte) 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,			0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,			0, 0, 0, 0, 0, 0, 0, 0 };	/*	 * len += shift; for (int i = 0; shift < len; i++, shift += 4) { out[i] =	 * ((int) (buffer[shift] & 0xff)) | (((int) (buffer[shift + 1] & 0xff)) <<	 * 8) | (((int) (buffer[shift + 2] & 0xff)) << 16) | (((int)	 * buffer[shift + 3]) << 24); }	 */	private final void decode( final byte buffer[], final int shift, final int[] out) {		out[0] = (buffer[shift] & 0xff) | ((buffer[shift + 1] & 0xff) << 8)				| ((buffer[shift + 2] & 0xff) << 16)				| (buffer[shift + 3] << 24);		out[1] = (buffer[shift + 4] & 0xff) | ((buffer[shift + 5] & 0xff) << 8)				| ((buffer[shift + 6] & 0xff) << 16)				| (buffer[shift + 7] << 24);		out[2] = (buffer[shift + 8] & 0xff) | ((buffer[shift + 9] & 0xff) << 8)				| ((buffer[shift + 10] & 0xff) << 16)				| (buffer[shift + 11] << 24);		out[3] = (buffer[shift + 12] & 0xff)				| ((buffer[shift + 13] & 0xff) << 8)				| ((buffer[shift + 14] & 0xff) << 16)				| (buffer[shift + 15] << 24);		out[4] = (buffer[shift + 16] & 0xff)				| ((buffer[shift + 17] & 0xff) << 8)				| ((buffer[shift + 18] & 0xff) << 16)				| (buffer[shift + 19] << 24);		out[5] = (buffer[shift + 20] & 0xff)				| ((buffer[shift + 21] & 0xff) << 8)				| ((buffer[shift + 22] & 0xff) << 16)				| (buffer[shift + 23] << 24);		out[6] = (buffer[shift + 24] & 0xff)				| ((buffer[shift + 25] & 0xff) << 8)				| ((buffer[shift + 26] & 0xff) << 16)				| (buffer[shift + 27] << 24);		out[7] = (buffer[shift + 28] & 0xff)				| ((buffer[shift + 29] & 0xff) << 8)				| ((buffer[shift + 30] & 0xff) << 16)				| (buffer[shift + 31] << 24);		out[8] = (buffer[shift + 32] & 0xff)				| ((buffer[shift + 33] & 0xff) << 8)				| ((buffer[shift + 34] & 0xff) << 16)				| (buffer[shift + 35] << 24);		out[9] = (buffer[shift + 36] & 0xff)				| ((buffer[shift + 37] & 0xff) << 8)				| ((buffer[shift + 38] & 0xff) << 16)				| (buffer[shift + 39] << 24);		out[10] = (buffer[shift + 40] & 0xff)				| ((buffer[shift + 41] & 0xff) << 8)				| ((buffer[shift + 42] & 0xff) << 16)				| (buffer[shift + 43] << 24);		out[11] = (buffer[shift + 44] & 0xff)				| ((buffer[shift + 45] & 0xff) << 8)				| ((buffer[shift + 46] & 0xff) << 16)				| (buffer[shift + 47] << 24);		out[12] = (buffer[shift + 48] & 0xff)				| ((buffer[shift + 49] & 0xff) << 8)				| ((buffer[shift + 50] & 0xff) << 16)				| (buffer[shift + 51] << 24);		out[13] = (buffer[shift + 52] & 0xff)				| ((buffer[shift + 53] & 0xff) << 8)				| ((buffer[shift + 54] & 0xff) << 16)				| (buffer[shift + 55] << 24);		out[14] = (buffer[shift + 56] & 0xff)				| ((buffer[shift + 57] & 0xff) << 8)				| ((buffer[shift + 58] & 0xff) << 16)				| (buffer[shift + 59] << 24);		out[15] = (buffer[shift + 60] & 0xff)				| ((buffer[shift + 61] & 0xff) << 8)				| ((buffer[shift + 62] & 0xff) << 16)				| (buffer[shift + 63] << 24);	}	private final void transform(MD5State state, byte buffer[], int shift, int[] decode_buf) {		int a = state.state[0], b = state.state[1], c = state.state[2], d = state.state[3], x[] = decode_buf;		decode(buffer, shift, decode_buf);		/* Round 1 */		a += ((b & c) | (~b & d)) + x[0] + 0xd76aa478; /* 1 */		a = ((a << 7) | (a >>> 25)) + b;		d += ((a & b) | (~a & c)) + x[1] + 0xe8c7b756; /* 2 */		d = ((d << 12) | (d >>> 20)) + a;		c += ((d & a) | (~d & b)) + x[2] + 0x242070db; /* 3 */		c = ((c << 17) | (c >>> 15)) + d;		b += ((c & d) | (~c & a)) + x[3] + 0xc1bdceee; /* 4 */		b = ((b << 22) | (b >>> 10)) + c;		a += ((b & c) | (~b & d)) + x[4] + 0xf57c0faf; /* 5 */		a = ((a << 7) | (a >>> 25)) + b;		d += ((a & b) | (~a & c)) + x[5] + 0x4787c62a; /* 6 */		d = ((d << 12) | (d >>> 20)) + a;		c += ((d & a) | (~d & b)) + x[6] + 0xa8304613; /* 7 */		c = ((c << 17) | (c >>> 15)) + d;		b += ((c & d) | (~c & a)) + x[7] + 0xfd469501; /* 8 */		b = ((b << 22) | (b >>> 10)) + c;		a += ((b & c) | (~b & d)) + x[8] + 0x698098d8; /* 9 */		a = ((a << 7) | (a >>> 25)) + b;		d += ((a & b) | (~a & c)) + x[9] + 0x8b44f7af; /* 10 */		d = ((d << 12) | (d >>> 20)) + a;		c += ((d & a) | (~d & b)) + x[10] + 0xffff5bb1; /* 11 */		c = ((c << 17) | (c >>> 15)) + d;		b += ((c & d) | (~c & a)) + x[11] + 0x895cd7be; /* 12 */		b = ((b << 22) | (b >>> 10)) + c;		a += ((b & c) | (~b & d)) + x[12] + 0x6b901122; /* 13 */		a = ((a << 7) | (a >>> 25)) + b;		d += ((a & b) | (~a & c)) + x[13] + 0xfd987193; /* 14 */		d = ((d << 12) | (d >>> 20)) + a;		c += ((d & a) | (~d & b)) + x[14] + 0xa679438e; /* 15 */		c = ((c << 17) | (c >>> 15)) + d;		b += ((c & d) | (~c & a)) + x[15] + 0x49b40821; /* 16 */		b = ((b << 22) | (b >>> 10)) + c;		/* Round 2 */		a += ((b & d) | (c & ~d)) + x[1] + 0xf61e2562; /* 17 */		a = ((a << 5) | (a >>> 27)) + b;		d += ((a & c) | (b & ~c)) + x[6] + 0xc040b340; /* 18 */		d = ((d << 9) | (d >>> 23)) + a;		c += ((d & b) | (a & ~b)) + x[11] + 0x265e5a51; /* 19 */		c = ((c << 14) | (c >>> 18)) + d;		b += ((c & a) | (d & ~a)) + x[0] + 0xe9b6c7aa; /* 20 */		b = ((b << 20) | (b >>> 12)) + c;		a += ((b & d) | (c & ~d)) + x[5] + 0xd62f105d; /* 21 */		a = ((a << 5) | (a >>> 27)) + b;		d += ((a & c) | (b & ~c)) + x[10] + 0x02441453; /* 22 */		d = ((d << 9) | (d >>> 23)) + a;		c += ((d & b) | (a & ~b)) + x[15] + 0xd8a1e681; /* 23 */		c = ((c << 14) | (c >>> 18)) + d;		b += ((c & a) | (d & ~a)) + x[4] + 0xe7d3fbc8; /* 24 */		b = ((b << 20) | (b >>> 12)) + c;		a += ((b & d) | (c & ~d)) + x[9] + 0x21e1cde6; /* 25 */		a = ((a << 5) | (a >>> 27)) + b;		d += ((a & c) | (b & ~c)) + x[14] + 0xc33707d6; /* 26 */		d = ((d << 9) | (d >>> 23)) + a;		c += ((d & b) | (a & ~b)) + x[3] + 0xf4d50d87; /* 27 */		c = ((c << 14) | (c >>> 18)) + d;		b += ((c & a) | (d & ~a)) + x[8] + 0x455a14ed; /* 28 */		b = ((b << 20) | (b >>> 12)) + c;		a += ((b & d) | (c & ~d)) + x[13] + 0xa9e3e905; /* 29 */		a = ((a << 5) | (a >>> 27)) + b;		d += ((a & c) | (b & ~c)) + x[2] + 0xfcefa3f8; /* 30 */		d = ((d << 9) | (d >>> 23)) + a;		c += ((d & b) | (a & ~b)) + x[7] + 0x676f02d9; /* 31 */		c = ((c << 14) | (c >>> 18)) + d;		b += ((c & a) | (d & ~a)) + x[12] + 0x8d2a4c8a; /* 32 */		b = ((b << 20) | (b >>> 12)) + c;		/* Round 3 */		a += (b ^ c ^ d) + x[5] + 0xfffa3942; /* 33 */		a = ((a << 4) | (a >>> 28)) + b;		d += (a ^ b ^ c) + x[8] + 0x8771f681; /* 34 */		d = ((d << 11) | (d >>> 21)) + a;		c += (d ^ a ^ b) + x[11] + 0x6d9d6122; /* 35 */		c = ((c << 16) | (c >>> 16)) + d;		b += (c ^ d ^ a) + x[14] + 0xfde5380c; /* 36 */		b = ((b << 23) | (b >>> 9)) + c;