/*
 * Copyright (c) 2003, 2012, Oracle and/or its affiliates. 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.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.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.
Author: Andreas Sterbenz
Since: 1.5
/** * 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 * @author Andreas Sterbenz */
public final class MD2 extends DigestBase { // state, 48 ints private int[] X; // checksum, 16 ints. they are really bytes, but byte arithmetic in // the JVM is much slower that int arithmetic. private int[] C; // temporary store for checksum C during final digest private byte[] cBytes;
Create a new MD2 digest. Called by the JCA framework
/** * 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]; } public Object clone() throws CloneNotSupportedException { MD2 copy = (MD2) super.clone(); copy.X = copy.X.clone(); copy.C = copy.C.clone(); copy.cBytes = new byte[16]; return copy; } // 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 static final 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 static final 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; } } }