| /* MessageDigest.java --- The message digest interface. |
| Copyright (C) 1999, 2002, 2003 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., 59 Temple Place, Suite 330, Boston, MA |
| 02111-1307 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; |
| |
| /** |
| * <p>This <code>MessageDigest</code> class provides applications the |
| * functionality of a message digest algorithm, such as <i>MD5</i> or <i>SHA</i>. |
| * Message digests are secure one-way hash functions that take arbitrary-sized |
| * data and output a fixed-length hash value.</p> |
| * |
| * <p>A <code>MessageDigest</code> object starts out initialized. The data is |
| * processed through it using the <code>update()</code> methods. At any point |
| * <code>reset()</code> can be called to reset the digest. Once all the data to |
| * be updated has been updated, one of the <code>digest()</code> methods should |
| * be called to complete the hash computation.</p> |
| * |
| * <p>The <code>digest()</code> method can be called <b>once</b> for a given |
| * number of updates. After <code>digest()</code> has been called, the |
| * <code>MessageDigest</code> object is <b>reset</b> to its initialized state. |
| * </p> |
| * |
| * <p>Implementations are free to implement the {@link Cloneable} interface. |
| * Client applications can test cloneability by attempting cloning and catching |
| * the {@link CloneNotSupportedException}: |
| * |
| * <pre> |
| * MessageDigest md = MessageDigest.getInstance("SHA"); |
| * try |
| * { |
| * md.update(toChapter1); |
| * MessageDigest tc1 = md.clone(); |
| * byte[] toChapter1Digest = tc1.digest(); |
| * md.update(toChapter2); |
| * // ... |
| * } |
| * catch (CloneNotSupportedException x) |
| * { |
| * throw new DigestException("couldn't make digest of partial content"); |
| * } |
| * </pre> |
| * |
| * <p>Note that if a given implementation is not cloneable, it is still possible |
| * to compute intermediate digests by instantiating several instances, if the |
| * number of digests is known in advance.</p> |
| * |
| * <p>Note that this class is abstract and extends from {@link MessageDigestSpi} |
| * for historical reasons. Application developers should only take notice of the |
| * methods defined in this <code>MessageDigest</code> class; all the methods in |
| * the superclass are intended for cryptographic service providers who wish to |
| * supply their own implementations of message digest algorithms.</p> |
| * |
| * @see MessageDigestSpi |
| * @see Provider |
| * @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; |
| |
| /** |
| * Creates a message digest with the specified algorithm name. |
| * |
| * @param algorithm the standard name of the digest algorithm. |
| * See Appendix A in the Java Cryptography Architecture API |
| * Specification & Reference for information about standard |
| * algorithm names. |
| */ |
| protected MessageDigest(String algorithm) |
| { |
| this.algorithm = algorithm; |
| provider = null; |
| } |
| |
| /** |
| * Generates a <code>MessageDigest</code> object that implements the specified |
| * digest algorithm. If the default provider package provides an |
| * implementation of the requested digest algorithm, an instance of |
| * <code>MessageDigest</code> containing that implementation is returned. If |
| * the algorithm is not available in the default package, other packages are |
| * searched. |
| * |
| * @param algorithm the name of the algorithm requested. See Appendix A in the |
| * Java Cryptography Architecture API Specification & Reference for |
| * information about standard algorithm names. |
| * @return a Message Digest object implementing the specified algorithm. |
| * @throws NoSuchAlgorithmException if the algorithm is not available in the |
| * caller's environment. |
| */ |
| 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); |
| } |
| |
| /** |
| * Generates a <code>MessageDigest</code> object implementing the specified |
| * algorithm, as supplied from the specified provider, if such an algorithm is |
| * available from the provider. |
| * |
| * @param algorithm the name of the algorithm requested. See Appendix A in the |
| * Java Cryptography Architecture API Specification & Reference for |
| * information about standard algorithm names. |
| * @param provider the name of the provider. |
| * @return a Message Digest object implementing the specified algorithm. |
| * @throws NoSuchAlgorithmException if the algorithm is not available in the |
| * package supplied by the requested provider. |
| * @throws NoSuchProviderException if the provider is not available in the |
| * environment. |
| * @throws IllegalArgumentException if the provider name is null or empty. |
| * @see Provider |
| */ |
| public static MessageDigest getInstance(String algorithm, String provider) |
| throws NoSuchAlgorithmException, NoSuchProviderException |
| { |
| 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); |
| } |
| |
| /** |
| * Generates a <code>MessageDigest</code> object implementing the specified |
| * algorithm, as supplied from the specified provider, if such an algorithm |
| * is available from the provider. Note: the provider doesn't have to be |
| * registered. |
| * |
| * @param algorithm the name of the algorithm requested. See Appendix A in |
| * the Java Cryptography Architecture API Specification & Reference for |
| * information about standard algorithm names. |
| * @param provider the provider. |
| * @return a Message Digest object implementing the specified algorithm. |
| * @throws NoSuchAlgorithmException if the <code>algorithm</code> is not |
| * available in the package supplied by the requested <code>provider</code>. |
| * @throws IllegalArgumentException if the <code>provider</code> is |
| * <code>null</code>. |
| * @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 provider of this message digest object. |
| * |
| * @return the provider of this message digest object. |
| */ |
| public final Provider getProvider() |
| { |
| return provider; |
| } |
| |
| /** |
| * Updates the digest using the specified byte. |
| * |
| * @param input the byte with which to update the digest. |
| */ |
| public void update(byte input) |
| { |
| engineUpdate(input); |
| } |
| |
| /** |
| * Updates the digest using the specified array of bytes, starting at the |
| * specified offset. |
| * |
| * @param input the array of bytes. |
| * @param offset the offset to start from in the array of bytes. |
| * @param len the number of bytes to use, starting at offset. |
| */ |
| public void update(byte[] input, int offset, int len) |
| { |
| engineUpdate(input, offset, len); |
| } |
| |
| /** |
| * Updates the digest using the specified array of bytes. |
| * |
| * @param input the array of bytes. |
| */ |
| public void update(byte[] input) |
| { |
| engineUpdate(input, 0, input.length); |
| } |
| |
| /** |
| * Completes the hash computation by performing final operations such as |
| * padding. The digest is reset after this call is made. |
| * |
| * @return the array of bytes for the resulting hash value. |
| */ |
| public byte[] digest() |
| { |
| return lastDigest = engineDigest(); |
| } |
| |
| /** |
| * Completes the hash computation by performing final operations such as |
| * padding. The digest is reset after this call is made. |
| * |
| * @param buf An output buffer for the computed digest. |
| * @param offset The offset into the output buffer to begin storing the digest. |
| * @param len The number of bytes within buf allotted for the digest. |
| * @return The number of bytes placed into buf. |
| * @throws DigestException if an error occurs. |
| */ |
| public int digest(byte[] buf, int offset, int len) throws DigestException |
| { |
| return engineDigest(buf, offset, len); |
| } |
| |
| /** |
| * Performs a final update on the digest using the specified array of bytes, |
| * then completes the digest computation. That is, this method first calls |
| * <code>update(input)</code>, passing the input array to the <code>update() |
| * </code> method, then calls <code>digest()</code>. |
| * |
| * @param input the input to be updated before the digest is completed. |
| * @return the array of bytes for the resulting hash value. |
| */ |
| public byte[] digest(byte[] input) |
| { |
| update(input); |
| return digest(); |
| } |
| |
| /** |
| * Returns a string representation of this message digest object. |
| * |
| * @return a string representation of the object. |
| */ |
| public String toString() |
| { |
| return (getClass()).getName() + " Message Digest <" + digestToString() + ">"; |
| } |
| |
| /** |
| * Compares two digests for equality. Does a simple byte compare. |
| * |
| * @param digesta one of the digests to compare. |
| * @param digestb the other digest to compare. |
| * @return <code>true</code> if the digests 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 the digest for further use. */ |
| public void reset() |
| { |
| engineReset(); |
| } |
| |
| /** |
| * Returns a string that identifies the algorithm, independent of |
| * implementation details. The name should be a standard Java Security name |
| * (such as <code>"SHA"</code>, <code>"MD5"</code>, and so on). See Appendix |
| * A in the Java Cryptography Architecture API Specification & Reference |
| * for information about standard algorithm names. |
| * |
| * @return the name of the algorithm. |
| */ |
| public final String getAlgorithm() |
| { |
| return algorithm; |
| } |
| |
| /** |
| * Returns the length of the digest in bytes, or <code>0</code> if this |
| * operation is not supported by the provider and the implementation is not |
| * cloneable. |
| * |
| * @return the digest length in bytes, or <code>0</code> if this operation is |
| * not supported by the provider and the implementation is not cloneable. |
| * @since 1.2 |
| */ |
| public final int getDigestLength() |
| { |
| return engineGetDigestLength(); |
| } |
| |
| /** |
| * Returns a clone if the implementation is cloneable. |
| * |
| * @return a clone if the implementation is cloneable. |
| * @throws CloneNotSupportedException if this is called on an implementation |
| * that does not support {@link Cloneable}. |
| */ |
| 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(); |
| } |
| } |