/*
* Copyright 2003 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code 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. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code 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 in the LICENSE file that
* accompanied this code).
*
* 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 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package sun.security.provider;
import java.util.Arrays;
/**
* Implementation for the MD2 algorithm, see RFC1319. It is very slow and
* not particular secure. It is only supported to be able to verify
* RSA/Verisign root certificates signed using MD2withRSA. It should not
* be used for anything else.
*
* @since 1.5
* @version 1.9, 05/05/07
* @author Andreas Sterbenz
*/
public final class MD2 extends DigestBase {
// state, 48 ints
private final int[] X;
// checksum, 16 ints. they are really bytes, but byte arithmetic in
// the JVM is much slower that int arithmetic.
private final int[] C;
// temporary store for checksum C during final digest
private final byte[] cBytes;
/**
* Create a new MD2 digest. Called by the JCA framework
*/
public MD2() {
super("MD2", 16, 16);
X = new int[48];
C = new int[16];
cBytes = new byte[16];
}
private MD2(MD2 base) {
super(base);
this.X = (int[])base.X.clone();
this.C = (int[])base.C.clone();
cBytes = new byte[16];
}
public Object clone() {
return new MD2(this);
}
// reset state and checksum
void implReset() {
Arrays.fill(X, 0);
Arrays.fill(C, 0);
}
// finish the digest
void implDigest(byte[] out, int ofs) {
int padValue = 16 - ((int)bytesProcessed & 15);
engineUpdate(PADDING[padValue], 0, padValue);
for (int i = 0; i < 16; i++) {
cBytes[i] = (byte)C[i];
}
implCompress(cBytes, 0);
for (int i = 0; i < 16; i++) {
out[ofs + i] = (byte)X[i];
}
}
// one iteration of the compression function
void implCompress(byte[] b, int ofs) {
for (int i = 0; i < 16; i++) {
int k = b[ofs + i] & 0xff;
X[16 + i] = k;
X[32 + i] = k ^ X[i];
}
// update the checksum
int t = C[15];
for (int i = 0; i < 16; i++) {
t = (C[i] ^= S[X[16 + i] ^ t]);
}
t = 0;
for (int i = 0; i < 18; i++) {
for (int j = 0; j < 48; j++) {
t = (X[j] ^= S[t]);
}
t = (t + i) & 0xff;
}
}
// substitution table derived from Pi. Copied from the RFC.
private final static int[] S = new int[] {
41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
31, 26, 219, 153, 141, 51, 159, 17, 131, 20,
};
// digest padding. 17 element array.
// padding[0] is null
// padding[i] is an array of i time the byte value i (i = 1..16)
private final static byte[][] PADDING;
static {
PADDING = new byte[17][];
for (int i = 1; i < 17; i++) {
byte[] b = new byte[i];
Arrays.fill(b, (byte)i);
PADDING[i] = b;
}
}
}
|