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Diffstat (limited to 'gcc-4.4.3/libjava/classpath/gnu/javax/crypto/mac/TMMH16.java')
| -rw-r--r-- | gcc-4.4.3/libjava/classpath/gnu/javax/crypto/mac/TMMH16.java | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/gcc-4.4.3/libjava/classpath/gnu/javax/crypto/mac/TMMH16.java b/gcc-4.4.3/libjava/classpath/gnu/javax/crypto/mac/TMMH16.java new file mode 100644 index 000000000..0a7b4a6ca --- /dev/null +++ b/gcc-4.4.3/libjava/classpath/gnu/javax/crypto/mac/TMMH16.java @@ -0,0 +1,339 @@ +/* TMMH16.java -- + Copyright (C) 2001, 2002, 2006 Free Software Foundation, Inc. + +This file is a part of GNU Classpath. + +GNU Classpath is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 2 of the License, or (at +your option) any later version. + +GNU Classpath 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 for more details. + +You should have received a copy of the GNU General Public License +along with GNU Classpath; if not, write to the Free Software +Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 +USA + +Linking this library statically or dynamically with other modules is +making a combined work based on this library. Thus, the terms and +conditions of the GNU General Public License cover the whole +combination. + +As a special exception, the copyright holders of this library give you +permission to link this library with independent modules to produce an +executable, regardless of the license terms of these independent +modules, and to copy and distribute the resulting executable under +terms of your choice, provided that you also meet, for each linked +independent module, the terms and conditions of the license of that +module. An independent module is a module which is not derived from +or based on this library. If you modify this library, you may extend +this exception to your version of the library, but you are not +obligated to do so. If you do not wish to do so, delete this +exception statement from your version. */ + + +package gnu.javax.crypto.mac; + +import gnu.java.security.Registry; +import gnu.java.security.prng.IRandom; +import gnu.java.security.prng.LimitReachedException; + +import java.security.InvalidKeyException; +import java.util.Map; + +/** + * <i>TMMH</i> is a <i>universal</i> hash function suitable for message + * authentication in the Wegman-Carter paradigm, as in the Stream Cipher + * Security Transform. It is simple, quick, and especially appropriate for + * Digital Signal Processors and other processors with a fast multiply + * operation, though a straightforward implementation requires storage equal in + * length to the largest message to be hashed. + * <p> + * <i>TMMH</i> is a simple hash function which maps a key and a message to a + * hash value. There are two versions of TMMH: TMMH/16 and TMMH/32. <i>TMMH</i> + * can be used as a message authentication code, as described in Section 5 (see + * References). + * <p> + * The key, message, and hash value are all octet strings, and the lengths of + * these quantities are denoted as <code>KEY_LENGTH</code>, + * <code>MESSAGE_LENGTH</code>, and <code>TAG_LENGTH</code>, respectively. + * The values of <code>KEY_LENGTH</code> and <code>TAG_LENGTH</code> + * <bold>MUST</bold> be fixed for any particular fixed value of the key, and + * must obey the alignment restrictions described below. + * <p> + * The parameter <code>MAX_HASH_LENGTH</code>, which denotes the maximum + * value which <code>MESSAGE_LENGTH</code> may take, is equal to + * <code>KEY_LENGTH - TAG_LENGTH</code>. + * <p> + * References: + * <ol> + * <li><a + * href="http://www.ietf.org/internet-drafts/draft-mcgrew-saag-tmmh-01.txt"> The + * Truncated Multi-Modular Hash Function (TMMH)</a>, David A. McGrew.</li> + * </ol> + */ +public class TMMH16 + extends BaseMac + implements Cloneable +{ + public static final String TAG_LENGTH = "gnu.crypto.mac.tmmh.tag.length"; + public static final String KEYSTREAM = "gnu.crypto.mac.tmmh.keystream"; + public static final String PREFIX = "gnu.crypto.mac.tmmh.prefix"; + private static final int P = (1 << 16) + 1; // the TMMH/16 prime + /** caches the result of the correctness test, once executed. */ + private static Boolean valid; + private int tagWords = 0; // the tagLength expressed in words + private IRandom keystream = null; // the keystream generator + private byte[] prefix; // mask to use when operating as an authentication f. + private long keyWords; // key words counter + private long msgLength; // in bytes + private long msgWords; // should be = msgLength * WORD_LENGTH + private int[] context; // the tmmh running context; length == TAG_WORDS + private int[] K0; // the first TAG_WORDS words of the keystream + private int[] Ki; // the sliding TAG_WORDS words of the keystream + private int Mi; // current message word being constructed + + /** Trivial 0-arguments constructor. */ + public TMMH16() + { + super(Registry.TMMH16); + } + + public int macSize() + { + return tagWords * 2; + } + + public void init(Map attributes) throws InvalidKeyException, + IllegalStateException + { + int wantTagLength = 0; + Integer tagLength = (Integer) attributes.get(TAG_LENGTH); // get tag length + if (tagLength == null) + { + if (tagWords == 0) // was never set + throw new IllegalArgumentException(TAG_LENGTH); + // else re-use + } + else // check if positive and is divisible by WORD_LENGTH + { + wantTagLength = tagLength.intValue(); + if (wantTagLength < 2 || (wantTagLength % 2 != 0)) + throw new IllegalArgumentException(TAG_LENGTH); + else if (wantTagLength > (512 / 8)) // 512-bits is our maximum + throw new IllegalArgumentException(TAG_LENGTH); + + tagWords = wantTagLength / 2; // init local vars + K0 = new int[tagWords]; + Ki = new int[tagWords]; + context = new int[tagWords]; + } + + prefix = (byte[]) attributes.get(PREFIX); + if (prefix == null) // default to all-zeroes + prefix = new byte[tagWords * 2]; + else // ensure it's as long as it should + { + if (prefix.length != tagWords * 2) + throw new IllegalArgumentException(PREFIX); + } + + IRandom prng = (IRandom) attributes.get(KEYSTREAM); // get keystream + if (prng == null) + { + if (keystream == null) + throw new IllegalArgumentException(KEYSTREAM); + // else reuse + } + else + keystream = prng; + + reset(); // reset context variables + for (int i = 0; i < tagWords; i++) // init starting key words + Ki[i] = K0[i] = getNextKeyWord(keystream); + } + + // The words of the key are denoted as K[1], K[2], ..., K[KEY_WORDS], and the + // words of the message (after zero padding, if needed) are denoted as M[1], + // M[2], ..., M[MSG_WORDS], where MSG_WORDS is the smallest number such that + // 2 * MSG_WORDS is at least MESSAGE_LENGTH, and KEY_WORDS is KEY_LENGTH / 2. + // + // If MESSAGE_LENGTH is greater than MAX_HASH_LENGTH, then the value of + // TMMH/16 is undefined. Implementations MUST indicate an error if asked to + // hash a message with such a length. Otherwise, the hash value is defined + // to be the length TAG_WORDS sequence of words in which the j-th word in the + // sequence is defined as + // + // [ [ K[j] * MESSAGE_LENGTH +32 K[j+1] * M[1] +32 K[j+2] * M[2] + // +32 ... K[j+MSG_WORDS] * M[MSG_WORDS] ] modulo p ] modulo 2^16 + // + // where j ranges from 1 to TAG_WORDS. + public void update(byte b) + { + this.update(b, keystream); + } + + public void update(byte[] b, int offset, int len) + { + for (int i = 0; i < len; i++) + this.update(b[offset + i], keystream); + } + + // For TMMH/16, KEY_LENGTH and TAG_LENGTH MUST be a multiple of two. The key, + // message, and hash value are treated as a sequence of unsigned sixteen bit + // integers in network byte order. (In this section, we call such an integer + // a word.) If MESSAGE_LENGTH is odd, then a zero byte is appended to the + // message to align it on a word boundary, though this process does not + // change the value of MESSAGE_LENGTH. + // + // ... Otherwise, the hash value is defined to be the length TAG_WORDS + // sequence of words in which the j-th word in the sequence is defined as + // + // [ [ K[j] * MESSAGE_LENGTH +32 K[j+1] * M[1] +32 K[j+2] * M[2] + // +32 ... K[j+MSG_WORDS] * M[MSG_WORDS] ] modulo p ] modulo 2^16 + // + // where j ranges from 1 to TAG_WORDS. + // + // Here, TAG_WORDS is equal to TAG_LENGTH / 2, and p is equal to 2^16 + 1. + // The symbol * denotes multiplication and the symbol +32 denotes addition + // modulo 2^32. + public byte[] digest() + { + return this.digest(keystream); + } + + public void reset() + { + msgLength = msgWords = keyWords = 0L; + Mi = 0; + for (int i = 0; i < tagWords; i++) + context[i] = 0; + } + + public boolean selfTest() + { + if (valid == null) + { + // TODO: compute and test equality with one known vector + valid = Boolean.TRUE; + } + return valid.booleanValue(); + } + + public Object clone() throws CloneNotSupportedException + { + TMMH16 result = (TMMH16) super.clone(); + if (this.keystream != null) + result.keystream = (IRandom) this.keystream.clone(); + if (this.prefix != null) + result.prefix = (byte[]) this.prefix.clone(); + if (this.context != null) + result.context = (int[]) this.context.clone(); + if (this.K0 != null) + result.K0 = (int[]) this.K0.clone(); + if (this.Ki != null) + result.Ki = (int[]) this.Ki.clone(); + return result; + } + + /** + * Similar to the same method with one argument, but uses the designated + * random number generator to compute needed keying material. + * + * @param b the byte to process. + * @param prng the source of randomness to use. + */ + public void update(byte b, IRandom prng) + { + Mi <<= 8; // update message buffer + Mi |= b & 0xFF; + msgLength++; // update message length (bytes) + if (msgLength % 2 == 0) // got a full word + { + msgWords++; // update message words counter + System.arraycopy(Ki, 1, Ki, 0, tagWords - 1); // 1. shift Ki up by 1 + Ki[tagWords - 1] = getNextKeyWord(prng); // 2. fill last box of Ki + long t; // temp var to allow working in modulo 2^32 + for (int i = 0; i < tagWords; i++) // 3. update context + { + t = context[i] & 0xFFFFFFFFL; + t += Ki[i] * Mi; + context[i] = (int) t; + } + Mi = 0; // reset message buffer + } + } + + /** + * Similar to the same method with three arguments, but uses the designated + * random number generator to compute needed keying material. + * + * @param b the byte array to process. + * @param offset the starting offset in <code>b</code> to start considering + * the bytes to process. + * @param len the number of bytes in <code>b</code> starting from + * <code>offset</code> to process. + * @param prng the source of randomness to use. + */ + public void update(byte[] b, int offset, int len, IRandom prng) + { + for (int i = 0; i < len; i++) + this.update(b[offset + i], prng); + } + + /** + * Similar to the same method with no arguments, but uses the designated + * random number generator to compute needed keying material. + * + * @param prng the source of randomness to use. + * @return the final result of the algorithm. + */ + public byte[] digest(IRandom prng) + { + doFinalRound(prng); + byte[] result = new byte[tagWords * 2]; + for (int i = 0, j = 0; i < tagWords; i++) + { + result[j] = (byte)((context[i] >>> 8) ^ prefix[j]); + j++; + result[j] = (byte)(context[i] ^ prefix[j]); + j++; + } + reset(); + return result; + } + + private int getNextKeyWord(IRandom prng) + { + int result = 0; + try + { + result = (prng.nextByte() & 0xFF) << 8 | (prng.nextByte() & 0xFF); + } + catch (LimitReachedException x) + { + throw new RuntimeException(String.valueOf(x)); + } + keyWords++; // update key words counter + return result; + } + + private void doFinalRound(IRandom prng) + { + long limit = msgLength; // formula works on real message length + while (msgLength % 2 != 0) + update((byte) 0x00, prng); + long t; + for (int i = 0; i < tagWords; i++) + { + t = context[i] & 0xFFFFFFFFL; + t += K0[i] * limit; + t %= P; + context[i] = (int) t; + } + } +} |