001: /*
002: * Copyright 2003 Sun Microsystems, Inc. All Rights Reserved.
003: * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
004: *
005: * This code is free software; you can redistribute it and/or modify it
006: * under the terms of the GNU General Public License version 2 only, as
007: * published by the Free Software Foundation. Sun designates this
008: * particular file as subject to the "Classpath" exception as provided
009: * by Sun in the LICENSE file that accompanied this code.
010: *
011: * This code is distributed in the hope that it will be useful, but WITHOUT
012: * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
013: * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
014: * version 2 for more details (a copy is included in the LICENSE file that
015: * accompanied this code).
016: *
017: * You should have received a copy of the GNU General Public License version
018: * 2 along with this work; if not, write to the Free Software Foundation,
019: * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
020: *
021: * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
022: * CA 95054 USA or visit www.sun.com if you need additional information or
023: * have any questions.
024: */
025:
026: package sun.security.provider;
027:
028: import java.util.Arrays;
029:
030: /**
031: * Implementation for the MD2 algorithm, see RFC1319. It is very slow and
032: * not particular secure. It is only supported to be able to verify
033: * RSA/Verisign root certificates signed using MD2withRSA. It should not
034: * be used for anything else.
035: *
036: * @since 1.5
037: * @version 1.9, 05/05/07
038: * @author Andreas Sterbenz
039: */
040: public final class MD2 extends DigestBase {
041:
042: // state, 48 ints
043: private final int[] X;
044:
045: // checksum, 16 ints. they are really bytes, but byte arithmetic in
046: // the JVM is much slower that int arithmetic.
047: private final int[] C;
048:
049: // temporary store for checksum C during final digest
050: private final byte[] cBytes;
051:
052: /**
053: * Create a new MD2 digest. Called by the JCA framework
054: */
055: public MD2() {
056: super ("MD2", 16, 16);
057: X = new int[48];
058: C = new int[16];
059: cBytes = new byte[16];
060: }
061:
062: private MD2(MD2 base) {
063: super (base);
064: this .X = (int[]) base.X.clone();
065: this .C = (int[]) base.C.clone();
066: cBytes = new byte[16];
067: }
068:
069: public Object clone() {
070: return new MD2(this );
071: }
072:
073: // reset state and checksum
074: void implReset() {
075: Arrays.fill(X, 0);
076: Arrays.fill(C, 0);
077: }
078:
079: // finish the digest
080: void implDigest(byte[] out, int ofs) {
081: int padValue = 16 - ((int) bytesProcessed & 15);
082: engineUpdate(PADDING[padValue], 0, padValue);
083: for (int i = 0; i < 16; i++) {
084: cBytes[i] = (byte) C[i];
085: }
086: implCompress(cBytes, 0);
087: for (int i = 0; i < 16; i++) {
088: out[ofs + i] = (byte) X[i];
089: }
090: }
091:
092: // one iteration of the compression function
093: void implCompress(byte[] b, int ofs) {
094: for (int i = 0; i < 16; i++) {
095: int k = b[ofs + i] & 0xff;
096: X[16 + i] = k;
097: X[32 + i] = k ^ X[i];
098: }
099:
100: // update the checksum
101: int t = C[15];
102: for (int i = 0; i < 16; i++) {
103: t = (C[i] ^= S[X[16 + i] ^ t]);
104: }
105:
106: t = 0;
107: for (int i = 0; i < 18; i++) {
108: for (int j = 0; j < 48; j++) {
109: t = (X[j] ^= S[t]);
110: }
111: t = (t + i) & 0xff;
112: }
113: }
114:
115: // substitution table derived from Pi. Copied from the RFC.
116: private final static int[] S = new int[] { 41, 46, 67, 201, 162,
117: 216, 124, 1, 61, 54, 84, 161, 236, 240, 6, 19, 98, 167, 5,
118: 243, 192, 199, 115, 140, 152, 147, 43, 217, 188, 76, 130,
119: 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
120: 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73,
121: 160, 251, 245, 142, 187, 47, 238, 122, 169, 104, 121, 145,
122: 21, 178, 7, 63, 148, 194, 16, 137, 11, 34, 95, 33, 128,
123: 127, 93, 154, 90, 144, 50, 39, 53, 62, 204, 231, 191, 247,
124: 151, 3, 255, 25, 48, 179, 72, 165, 181, 209, 215, 94, 146,
125: 42, 172, 86, 170, 198, 79, 184, 56, 210, 150, 164, 125,
126: 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157, 112,
127: 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2,
128: 27, 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52,
129: 64, 126, 15, 85, 71, 163, 35, 221, 81, 175, 58, 195, 92,
130: 249, 206, 186, 197, 234, 38, 44, 83, 13, 110, 133, 40, 132,
131: 9, 211, 223, 205, 244, 65, 129, 77, 82, 106, 220, 55, 200,
132: 108, 193, 171, 250, 36, 225, 123, 8, 12, 189, 177, 74, 120,
133: 136, 149, 139, 227, 99, 232, 109, 233, 203, 213, 254, 59,
134: 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228, 166, 119,
135: 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237, 31,
136: 26, 219, 153, 141, 51, 159, 17, 131, 20, };
137:
138: // digest padding. 17 element array.
139: // padding[0] is null
140: // padding[i] is an array of i time the byte value i (i = 1..16)
141: private final static byte[][] PADDING;
142:
143: static {
144: PADDING = new byte[17][];
145: for (int i = 1; i < 17; i++) {
146: byte[] b = new byte[i];
147: Arrays.fill(b, (byte) i);
148: PADDING[i] = b;
149: }
150: }
151:
152: }
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