Mega Code Archive
An implementation of Ron Rivests MD4 message digest algorithm
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//package org.apache.mina.proxy.utils;
import java.security.DigestException;
import java.security.MessageDigestSpi;
/**
* MD4.java - An implementation of Ron Rivest's MD4 message digest algorithm.
* The MD4 algorithm is designed to be quite fast on 32-bit machines. In
* addition, the MD4 algorithm does not require any large substitution
* tables.
*
* @see The <a href="http://www.ietf.org/rfc/rfc1320.txt">MD4</a> Message-
* Digest Algorithm by R. Rivest.
*
* @author <a href="http://mina.apache.org">Apache MINA Project</a>
* @since MINA 2.0.0-M3
*/
public class MD4 extends MessageDigestSpi {
/**
* The MD4 algorithm message digest length is 16 bytes wide.
*/
public static final int BYTE_DIGEST_LENGTH = 16;
/**
* The MD4 algorithm block length is 64 bytes wide.
*/
public static final int BYTE_BLOCK_LENGTH = 64;
/**
* The initial values of the four registers. RFC gives the values
* in LE so we converted it as JAVA uses BE endianness.
*/
private final static int A = 0x67452301;
private final static int B = 0xefcdab89;
private final static int C = 0x98badcfe;
private final static int D = 0x10325476;
/**
* The four registers initialized with the above IVs.
*/
private int a = A;
private int b = B;
private int c = C;
private int d = D;
/**
* Counts the total length of the data being digested.
*/
private long msgLength;
/**
* The internal buffer is {@link BLOCK_LENGTH} wide.
*/
private final byte[] buffer = new byte[BYTE_BLOCK_LENGTH];
/**
* Default constructor.
*/
public MD4() {
// Do nothing
}
/**
* Returns the digest length in bytes.
*
* @return the digest length in bytes.
*/
protected int engineGetDigestLength() {
return BYTE_DIGEST_LENGTH;
}
/**
* {@inheritDoc}
*/
protected void engineUpdate(byte b) {
int pos = (int) (msgLength % BYTE_BLOCK_LENGTH);
buffer[pos] = b;
msgLength++;
// If buffer contains enough data then process it.
if (pos == (BYTE_BLOCK_LENGTH - 1)) {
process(buffer, 0);
}
}
/**
* {@inheritDoc}
*/
protected void engineUpdate(byte[] b, int offset, int len) {
int pos = (int) (msgLength % BYTE_BLOCK_LENGTH);
int nbOfCharsToFillBuf = BYTE_BLOCK_LENGTH - pos;
int blkStart = 0;
msgLength += len;
// Process each full block
if (len >= nbOfCharsToFillBuf) {
System.arraycopy(b, offset, buffer, pos, nbOfCharsToFillBuf);
process(buffer, 0);
for (blkStart = nbOfCharsToFillBuf; blkStart + BYTE_BLOCK_LENGTH
- 1 < len; blkStart += BYTE_BLOCK_LENGTH) {
process(b, offset + blkStart);
}
pos = 0;
}
// Fill buffer with the remaining data
if (blkStart < len) {
System.arraycopy(b, offset + blkStart, buffer, pos, len - blkStart);
}
}
/**
* {@inheritDoc}
*/
protected byte[] engineDigest() {
byte[] p = pad();
engineUpdate(p, 0, p.length);
byte[] digest = { (byte) a, (byte) (a >>> 8), (byte) (a >>> 16),
(byte) (a >>> 24), (byte) b, (byte) (b >>> 8),
(byte) (b >>> 16), (byte) (b >>> 24), (byte) c,
(byte) (c >>> 8), (byte) (c >>> 16), (byte) (c >>> 24),
(byte) d, (byte) (d >>> 8), (byte) (d >>> 16),
(byte) (d >>> 24) };
engineReset();
return digest;
}
/**
* {@inheritDoc}
*/
protected int engineDigest(byte[] buf, int offset, int len)
throws DigestException {
if (offset < 0 || offset + len >= buf.length) {
throw new DigestException(
"Wrong offset or not enough space to store the digest");
}
int destLength = Math.min(len, BYTE_DIGEST_LENGTH);
System.arraycopy(engineDigest(), 0, buf, offset, destLength);
return destLength;
}
/**
* {@inheritDoc}
*/
protected void engineReset() {
a = A;
b = B;
c = C;
d = D;
msgLength = 0;
}
/**
* Pads the buffer by appending the byte 0x80, then append as many zero
* bytes as necessary to make the buffer length a multiple of 64 bytes.
* The last 8 bytes will be filled with the length of the buffer in bits.
* If there's no room to store the length in bits in the block i.e the block
* is larger than 56 bytes then an additionnal 64-bytes block is appended.
*
* @see sections 3.1 & 3.2 of the RFC 1320.
*
* @return the pad byte array
*/
private byte[] pad() {
int pos = (int) (msgLength % BYTE_BLOCK_LENGTH);
int padLength = (pos < 56) ? (64 - pos) : (128 - pos);
byte[] pad = new byte[padLength];
// First bit of the padding set to 1
pad[0] = (byte) 0x80;
long bits = msgLength << 3;
int index = padLength - 8;
for (int i = 0; i < 8; i++) {
pad[index++] = (byte) (bits >>> (i << 3));
}
return pad;
}
/**
* Process one 64-byte block. Algorithm is constituted by three rounds.
* Note that F, G and H functions were inlined for improved performance.
*
* @param in the byte array to process
* @param offset the offset at which the 64-byte block is stored
*/
private void process(byte[] in, int offset) {
// Save previous state.
int aa = a;
int bb = b;
int cc = c;
int dd = d;
// Copy the block to process into X array
int[] X = new int[16];
for (int i = 0; i < 16; i++) {
X[i] = (in[offset++] & 0xff) | (in[offset++] & 0xff) << 8
| (in[offset++] & 0xff) << 16 | (in[offset++] & 0xff) << 24;
}
// Round 1
a += ((b & c) | (~b & d)) + X[0];
a = a << 3 | a >>> (32 - 3);
d += ((a & b) | (~a & c)) + X[1];
d = d << 7 | d >>> (32 - 7);
c += ((d & a) | (~d & b)) + X[2];
c = c << 11 | c >>> (32 - 11);
b += ((c & d) | (~c & a)) + X[3];
b = b << 19 | b >>> (32 - 19);
a += ((b & c) | (~b & d)) + X[4];
a = a << 3 | a >>> (32 - 3);
d += ((a & b) | (~a & c)) + X[5];
d = d << 7 | d >>> (32 - 7);
c += ((d & a) | (~d & b)) + X[6];
c = c << 11 | c >>> (32 - 11);
b += ((c & d) | (~c & a)) + X[7];
b = b << 19 | b >>> (32 - 19);
a += ((b & c) | (~b & d)) + X[8];
a = a << 3 | a >>> (32 - 3);
d += ((a & b) | (~a & c)) + X[9];
d = d << 7 | d >>> (32 - 7);
c += ((d & a) | (~d & b)) + X[10];
c = c << 11 | c >>> (32 - 11);
b += ((c & d) | (~c & a)) + X[11];
b = b << 19 | b >>> (32 - 19);
a += ((b & c) | (~b & d)) + X[12];
a = a << 3 | a >>> (32 - 3);
d += ((a & b) | (~a & c)) + X[13];
d = d << 7 | d >>> (32 - 7);
c += ((d & a) | (~d & b)) + X[14];
c = c << 11 | c >>> (32 - 11);
b += ((c & d) | (~c & a)) + X[15];
b = b << 19 | b >>> (32 - 19);
// Round 2
a += ((b & (c | d)) | (c & d)) + X[0] + 0x5a827999;
a = a << 3 | a >>> (32 - 3);
d += ((a & (b | c)) | (b & c)) + X[4] + 0x5a827999;
d = d << 5 | d >>> (32 - 5);
c += ((d & (a | b)) | (a & b)) + X[8] + 0x5a827999;
c = c << 9 | c >>> (32 - 9);
b += ((c & (d | a)) | (d & a)) + X[12] + 0x5a827999;
b = b << 13 | b >>> (32 - 13);
a += ((b & (c | d)) | (c & d)) + X[1] + 0x5a827999;
a = a << 3 | a >>> (32 - 3);
d += ((a & (b | c)) | (b & c)) + X[5] + 0x5a827999;
d = d << 5 | d >>> (32 - 5);
c += ((d & (a | b)) | (a & b)) + X[9] + 0x5a827999;
c = c << 9 | c >>> (32 - 9);
b += ((c & (d | a)) | (d & a)) + X[13] + 0x5a827999;
b = b << 13 | b >>> (32 - 13);
a += ((b & (c | d)) | (c & d)) + X[2] + 0x5a827999;
a = a << 3 | a >>> (32 - 3);
d += ((a & (b | c)) | (b & c)) + X[6] + 0x5a827999;
d = d << 5 | d >>> (32 - 5);
c += ((d & (a | b)) | (a & b)) + X[10] + 0x5a827999;
c = c << 9 | c >>> (32 - 9);
b += ((c & (d | a)) | (d & a)) + X[14] + 0x5a827999;
b = b << 13 | b >>> (32 - 13);
a += ((b & (c | d)) | (c & d)) + X[3] + 0x5a827999;
a = a << 3 | a >>> (32 - 3);
d += ((a & (b | c)) | (b & c)) + X[7] + 0x5a827999;
d = d << 5 | d >>> (32 - 5);
c += ((d & (a | b)) | (a & b)) + X[11] + 0x5a827999;
c = c << 9 | c >>> (32 - 9);
b += ((c & (d | a)) | (d & a)) + X[15] + 0x5a827999;
b = b << 13 | b >>> (32 - 13);
// Round 3
a += (b ^ c ^ d) + X[0] + 0x6ed9eba1;
a = a << 3 | a >>> (32 - 3);
d += (a ^ b ^ c) + X[8] + 0x6ed9eba1;
d = d << 9 | d >>> (32 - 9);
c += (d ^ a ^ b) + X[4] + 0x6ed9eba1;
c = c << 11 | c >>> (32 - 11);
b += (c ^ d ^ a) + X[12] + 0x6ed9eba1;
b = b << 15 | b >>> (32 - 15);
a += (b ^ c ^ d) + X[2] + 0x6ed9eba1;
a = a << 3 | a >>> (32 - 3);
d += (a ^ b ^ c) + X[10] + 0x6ed9eba1;
d = d << 9 | d >>> (32 - 9);
c += (d ^ a ^ b) + X[6] + 0x6ed9eba1;
c = c << 11 | c >>> (32 - 11);
b += (c ^ d ^ a) + X[14] + 0x6ed9eba1;
b = b << 15 | b >>> (32 - 15);
a += (b ^ c ^ d) + X[1] + 0x6ed9eba1;
a = a << 3 | a >>> (32 - 3);
d += (a ^ b ^ c) + X[9] + 0x6ed9eba1;
d = d << 9 | d >>> (32 - 9);
c += (d ^ a ^ b) + X[5] + 0x6ed9eba1;
c = c << 11 | c >>> (32 - 11);
b += (c ^ d ^ a) + X[13] + 0x6ed9eba1;
b = b << 15 | b >>> (32 - 15);
a += (b ^ c ^ d) + X[3] + 0x6ed9eba1;
a = a << 3 | a >>> (32 - 3);
d += (a ^ b ^ c) + X[11] + 0x6ed9eba1;
d = d << 9 | d >>> (32 - 9);
c += (d ^ a ^ b) + X[7] + 0x6ed9eba1;
c = c << 11 | c >>> (32 - 11);
b += (c ^ d ^ a) + X[15] + 0x6ed9eba1;
b = b << 15 | b >>> (32 - 15);
//Update state.
a += aa;
b += bb;
c += cc;
d += dd;
}
}
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