/*
*
*
* Copyright 1990-2007 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version
* 2 only, as published by the Free Software Foundation.
*
* This program 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
* General Public License version 2 for more details (a copy is
* included at /legal/license.txt).
*
* You should have received a copy of the GNU General Public License
* version 2 along with this work; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa
* Clara, CA 95054 or visit www.sun.com if you need additional
* information or have any questions.
*/
package com.sun.midp.crypto;
/**
* Implements the MD5 hashing algorithm as described in IETF RFC 1321
* (see http://www.ietf.org/rfc/rfc1321.txt)
*/
final class MD5 extends MessageDigest {
/*
* The compute intensive operations are implemented in C
* based on the OpenSSL MD5 code (from pilotSSLeay). Here we
* replicate the state the C code needs.
*/
/** State needed for MD5 hash, four elements correspond to A, B, C, D. */
private int[] state = new int[4];
/** State needed for MD5 hash. */
private int[] num = new int[1];
/** Number of bits modulo 2^64 (LSB first) */
private int[] count = new int[2];
/** Input data. */
private int[] data = new int[16];
/** Create an MD5 digest object. */
MD5() {
reset();
}
/**
* Gets the message digest algorithm.
* @return algorithm implemented by this MessageDigest object
*/
public String getAlgorithm() {
return "MD5";
}
/**
* Gets the length (in bytes) of the hash.
* @return byte-length of the hash produced by this object
*/
public int getDigestLength() {
return 16;
}
/**
* Resets the MessageDigest to the initial state for further use.
*/
public void reset() {
count[0] = 0;
count[1] = 0;
// Load magic initialization constants.
state[0] = 0x67452301;
state[1] = 0xefcdab89;
state[2] = 0x98badcfe;
state[3] = 0x10325476;
for (int i = 0; i < 16; i++)
data[i] = 0;
num[0] = 0;
}
/**
* Accumulates a hash of the input data. Continues an MD5
* message-digest operation, processing another message
* block, and updating the internal context.
* @param inBuf input buffer of data to be hashed
* @param inOff offset within inBuf where input data begins
* @param inLen length (in bytes) of data to be hashed
* @see #doFinal(byte[], int, int, byte[], int)
*/
public void update(byte[] inBuf, int inOff, int inLen) {
if (inLen == 0) {
return;
}
// check parameters to prevent VM from crashing
int test = inBuf[inOff] + inBuf[inLen - 1] + inBuf[inOff + inLen - 1];
nativeUpdate(inBuf, inOff, inLen, state, num, count, data);
}
/**
* Accumulates a hash of the input data. Continues an MD5
* message-digest operation, processing another message
* block, and updating the internal context.
* @param inBuf input buffer of data to be hashed
* @param inOff offset within inBuf where input data begins
* @param inLen length (in bytes) of data to be hashed
* @param state internal hash state
* @param num internal hash state
* @param count internal hash state
* @param data internal hash state
*/
private static native void nativeUpdate(byte[] inBuf, int inOff,
int inLen, int[] state, int[] num, int[] count, int[] data);
/**
* Completes the hash computation by performing final operations
* such as padding. The digest is reset after this call is made.
*
* @param buf output buffer for the computed digest
*
* @param offset offset into the output buffer to begin storing the digest
*
* @param len number of bytes within buf allotted for the digest
*
* @return the number of bytes placed into <code>buf</code>
*
* @exception DigestException if an error occurs.
*/
public int digest(byte[] buf, int offset, int len) throws DigestException {
if (len < getDigestLength()) {
throw new DigestException("Buffer too short.");
}
// check the parameters to prevent a VM crash
int test = buf[offset] + buf[offset + getDigestLength() - 1];
nativeFinal(null, 0, 0, buf, offset, state, num, count, data);
return getDigestLength();
}
/**
* Generates a hash of all/last input data. Completes and returns the
* hash compuatation after performing final operations such as padding.
* The MessageDigest object is reset after this call.
* @param inBuf input buffer of data to be hashed
* @param inOff offset within inBuf where input data begins
* @param inLen length (in bytes) of data to be hashed
* @param outBuf output buffer where the hash should be placed
* @param outOff offset within outBuf where the resulting hash begins
* @param state internal hash state
* @param num internal hash state
* @param count internal hash state
* @param data internal hash state
*/
private static native void nativeFinal(byte[] inBuf, int inOff,
int inLen, byte[] outBuf, int outOff,
int[] state, int[] num, int[] count, int[] data);
/**
* Clones the MessageDigest object.
* @return a clone of this object
*/
public Object clone() {
MD5 cpy = new MD5();
System.arraycopy(this.state, 0, cpy.state, 0, 4);
System.arraycopy(this.num, 0, cpy.num, 0, 1);
System.arraycopy(this.data, 0, cpy.data, 0, 16);
System.arraycopy(this.count, 0, cpy.count, 0, 2);
return cpy;
}
}
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