| /* MessageDigest.java --- The message digest interface. |
| Copyright (C) 1999, 2002, 2003, 2006 Free Software Foundation, Inc. |
| |
| This file is 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, 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; see the file COPYING. If not, write to the |
| Free Software Foundation, Inc., 51 Franklin Street, 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 java.security; |
| |
| import gnu.java.security.Engine; |
| |
| /** |
| * Message digests are secure one-way hash functions that take arbitrary-sized |
| * data and output a fixed-length hash value. |
| * |
| * @see MessageDigestSpi |
| * @since JDK 1.1 |
| */ |
| public abstract class MessageDigest extends MessageDigestSpi |
| { |
| /** The service name for message digests. */ |
| private static final String MESSAGE_DIGEST = "MessageDigest"; |
| |
| private String algorithm; |
| Provider provider; |
| private byte[] lastDigest; |
| |
| /** |
| * Constructs a new instance of <code>MessageDigest</code> representing the |
| * specified algorithm. |
| * |
| * @param algorithm |
| * the name of the digest algorithm to use. |
| */ |
| protected MessageDigest(String algorithm) |
| { |
| this.algorithm = algorithm; |
| provider = null; |
| } |
| |
| /** |
| * Returns a new instance of <code>MessageDigest</code> representing the |
| * specified algorithm. |
| * |
| * @param algorithm |
| * the name of the digest algorithm to use. |
| * @return a new instance representing the desired algorithm. |
| * @throws NoSuchAlgorithmException |
| * if the algorithm is not implemented by any provider. |
| */ |
| public static MessageDigest getInstance(String algorithm) |
| throws NoSuchAlgorithmException |
| { |
| Provider[] p = Security.getProviders(); |
| for (int i = 0; i < p.length; i++) |
| { |
| try |
| { |
| return getInstance(algorithm, p[i]); |
| } |
| catch (NoSuchAlgorithmException ignored) |
| { |
| // Ignore. |
| } |
| } |
| |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| |
| /** |
| * Returns a new instance of <code>MessageDigest</code> representing the |
| * specified algorithm from a named provider. |
| * |
| * @param algorithm |
| * the name of the digest algorithm to use. |
| * @param provider |
| * the name of the provider to use. |
| * @return a new instance representing the desired algorithm. |
| * @throws NoSuchAlgorithmException |
| * if the algorithm is not implemented by the named provider. |
| * @throws NoSuchProviderException |
| * if the named provider was not found. |
| */ |
| public static MessageDigest getInstance(String algorithm, String provider) |
| throws NoSuchAlgorithmException, NoSuchProviderException |
| { |
| if (provider != null) |
| provider = provider.trim(); |
| |
| if (provider == null || provider.length() == 0) |
| throw new IllegalArgumentException("Illegal provider"); |
| |
| Provider p = Security.getProvider(provider); |
| if (p == null) |
| throw new NoSuchProviderException(provider); |
| |
| return getInstance(algorithm, p); |
| } |
| |
| /** |
| * Returns a new instance of <code>MessageDigest</code> representing the |
| * specified algorithm from a designated {@link Provider}. |
| * |
| * @param algorithm |
| * the name of the digest algorithm to use. |
| * @param provider |
| * the {@link Provider} to use. |
| * @return a new instance representing the desired algorithm. |
| * @throws IllegalArgumentException |
| * if <code>provider</code> is <code>null</code>. |
| * @throws NoSuchAlgorithmException |
| * if the algorithm is not implemented by {@link Provider}. |
| * @since 1.4 |
| * @see Provider |
| */ |
| public static MessageDigest getInstance(String algorithm, Provider provider) |
| throws NoSuchAlgorithmException |
| { |
| if (provider == null) |
| throw new IllegalArgumentException("Illegal provider"); |
| |
| MessageDigest result = null; |
| Object o = null; |
| try |
| { |
| o = Engine.getInstance(MESSAGE_DIGEST, algorithm, provider); |
| } |
| catch (java.lang.reflect.InvocationTargetException ite) |
| { |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| |
| if (o instanceof MessageDigestSpi) |
| { |
| result = new DummyMessageDigest((MessageDigestSpi) o, algorithm); |
| } |
| else if (o instanceof MessageDigest) |
| { |
| result = (MessageDigest) o; |
| result.algorithm = algorithm; |
| } |
| else |
| { |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| result.provider = provider; |
| return result; |
| } |
| |
| /** |
| * Returns the {@link Provider} of this instance. |
| * |
| * @return the {@link Provider} of this instance. |
| */ |
| public final Provider getProvider() |
| { |
| return provider; |
| } |
| |
| /** |
| * Updates the digest with the byte. |
| * |
| * @param input byte to update the digest with. |
| */ |
| public void update(byte input) |
| { |
| engineUpdate(input); |
| } |
| |
| /** |
| * Updates the digest with the bytes from the array starting from the |
| * specified offset and using the specified length of bytes. |
| * |
| * @param input |
| * bytes to update the digest with. |
| * @param offset |
| * the offset to start at. |
| * @param len |
| * length of the data to update with. |
| */ |
| public void update(byte[] input, int offset, int len) |
| { |
| engineUpdate(input, offset, len); |
| } |
| |
| /** |
| * Updates the digest with the bytes of an array. |
| * |
| * @param input bytes to update the digest with. |
| */ |
| public void update(byte[] input) |
| { |
| engineUpdate(input, 0, input.length); |
| } |
| |
| /** |
| * Computes the final digest of the stored data. |
| * |
| * @return a byte array representing the message digest. |
| */ |
| public byte[] digest() |
| { |
| return lastDigest = engineDigest(); |
| } |
| |
| /** |
| * Computes the final digest of the stored bytes and returns the result. |
| * |
| * @param buf |
| * an array of bytes to store the result in. |
| * @param offset |
| * an offset to start storing the result at. |
| * @param len |
| * the length of the buffer. |
| * @return Returns the length of the buffer. |
| */ |
| public int digest(byte[] buf, int offset, int len) throws DigestException |
| { |
| return engineDigest(buf, offset, len); |
| } |
| |
| /** |
| * Computes a final update using the input array of bytes, then computes a |
| * final digest and returns it. It calls {@link #update(byte[])} and then |
| * {@link #digest(byte[])}. |
| * |
| * @param input |
| * an array of bytes to perform final update with. |
| * @return a byte array representing the message digest. |
| */ |
| public byte[] digest(byte[] input) |
| { |
| update(input); |
| return digest(); |
| } |
| |
| /** |
| * Returns a string representation of this instance. |
| * |
| * @return a string representation of this instance. |
| */ |
| public String toString() |
| { |
| return (getClass()).getName() + " Message Digest <" + digestToString() + ">"; |
| } |
| |
| /** |
| * Does a simple byte comparison of the two digests. |
| * |
| * @param digesta |
| * first digest to compare. |
| * @param digestb |
| * second digest to compare. |
| * @return <code>true</code> if both are equal, <code>false</code> |
| * otherwise. |
| */ |
| public static boolean isEqual(byte[] digesta, byte[] digestb) |
| { |
| if (digesta.length != digestb.length) |
| return false; |
| |
| for (int i = digesta.length - 1; i >= 0; --i) |
| if (digesta[i] != digestb[i]) |
| return false; |
| |
| return true; |
| } |
| |
| /** Resets this instance. */ |
| public void reset() |
| { |
| engineReset(); |
| } |
| |
| /** |
| * Returns the name of message digest algorithm. |
| * |
| * @return the name of message digest algorithm. |
| */ |
| public final String getAlgorithm() |
| { |
| return algorithm; |
| } |
| |
| /** |
| * Returns the length of the message digest. The default is zero which means |
| * that the concrete implementation does not implement this method. |
| * |
| * @return length of the message digest. |
| * @since 1.2 |
| */ |
| public final int getDigestLength() |
| { |
| return engineGetDigestLength(); |
| } |
| |
| /** |
| * Returns a clone of this instance if cloning is supported. If it does not |
| * then a {@link CloneNotSupportedException} is thrown. Cloning depends on |
| * whether the subclass {@link MessageDigestSpi} implements {@link Cloneable} |
| * which contains the actual implementation of the appropriate algorithm. |
| * |
| * @return a clone of this instance. |
| * @throws CloneNotSupportedException |
| * the implementation does not support cloning. |
| */ |
| public Object clone() throws CloneNotSupportedException |
| { |
| return super.clone(); |
| } |
| |
| private String digestToString() |
| { |
| byte[] digest = lastDigest; |
| |
| if (digest == null) |
| return "incomplete"; |
| |
| StringBuffer buf = new StringBuffer(); |
| int len = digest.length; |
| for (int i = 0; i < len; ++i) |
| { |
| byte b = digest[i]; |
| byte high = (byte) ((b & 0xff) >>> 4); |
| byte low = (byte) (b & 0xf); |
| |
| buf.append(high > 9 ? ('a' - 10) + high : '0' + high); |
| buf.append(low > 9 ? ('a' - 10) + low : '0' + low); |
| } |
| |
| return buf.toString(); |
| } |
| } |