| |
| /* MessageDigest.java --- The message digest interface. |
| Copyright (C) 1999, 2002 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; |
| |
| public abstract class MessageDigest extends MessageDigestSpi |
| { |
| private String algorithm; |
| Provider provider; |
| private byte[] lastDigest; |
| |
| /** |
| Creates a MessageDigest representing the specified |
| algorithm. |
| |
| @param algorithm the name of digest algorithm to choose |
| */ |
| protected MessageDigest(String algorithm) |
| { |
| this.algorithm = algorithm; |
| provider = null; |
| } |
| |
| /** |
| Gets an instance of the MessageDigest class representing |
| the specified digest. If the algorithm is not found then, |
| it throws NoSuchAlgorithmException. |
| |
| @param algorithm the name of digest algorithm to choose |
| @return a MessageDigest representing the desired algorithm |
| |
| @exception NoSuchAlgorithmException if the algorithm is not implemented by |
| providers |
| */ |
| 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) {} |
| } |
| |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| |
| /** |
| Gets an instance of the MessageDigest class representing |
| the specified digest from the specified provider. If the |
| algorithm is not found then, it throws NoSuchAlgorithmException. |
| If the provider is not found, then it throws |
| NoSuchProviderException. |
| |
| @param algorithm the name of digest algorithm to choose |
| @param provider the name of the provider to find the algorithm in |
| @return a MessageDigest representing the desired algorithm |
| |
| @exception NoSuchAlgorithmException if the algorithm is not implemented by |
| the provider |
| @exception NoSuchProviderException if the provider is not found |
| */ |
| |
| public static MessageDigest getInstance(String algorithm, String provider) |
| throws NoSuchAlgorithmException, NoSuchProviderException |
| { |
| Provider p = Security.getProvider(provider); |
| |
| if (p == null) |
| throw new NoSuchProviderException(provider); |
| |
| return getInstance(algorithm, p); |
| } |
| |
| private static MessageDigest getInstance(String algorithm, Provider p) |
| throws NoSuchAlgorithmException |
| { |
| // try the name as is |
| String className = p.getProperty("MessageDigest." + algorithm); |
| if (className == null) { // try all uppercase |
| String upper = algorithm.toUpperCase(); |
| className = p.getProperty("MessageDigest." + upper); |
| if (className == null) { // try if it's an alias |
| String alias = p.getProperty("Alg.Alias.MessageDigest." +algorithm); |
| if (alias == null) { // try all-uppercase alias name |
| alias = p.getProperty("Alg.Alias.MessageDigest." +upper); |
| if (alias == null) { // spit the dummy |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| } |
| className = p.getProperty("MessageDigest." + alias); |
| if (className == null) { |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| } |
| } |
| return getInstance(className, algorithm, p); |
| } |
| |
| private static MessageDigest getInstance(String classname, |
| String algorithm, |
| Provider provider) |
| throws NoSuchAlgorithmException |
| { |
| if (classname == null) |
| throw new NoSuchAlgorithmException(algorithm); |
| |
| MessageDigest result = null; |
| try |
| { |
| Object obj = Class.forName(classname).newInstance(); |
| if (obj instanceof MessageDigest) { |
| result = (MessageDigest) obj; |
| result.algorithm = algorithm; |
| } else if (obj instanceof MessageDigestSpi) { |
| result = new DummyMessageDigest((MessageDigestSpi) obj, algorithm); |
| } else { |
| throw new ClassCastException("Class "+classname+" from Provider " |
| +provider.getName() |
| +" does not extend java.security.MessageDigestSpi"); |
| } |
| result.provider = provider; |
| return result; |
| } |
| catch (ClassNotFoundException cnfe) |
| { |
| throw new NoSuchAlgorithmException(algorithm + ": Class not found."); |
| } |
| catch (InstantiationException ie) |
| { |
| throw new NoSuchAlgorithmException(algorithm |
| + ": Class instantiation failed."); |
| } |
| catch (IllegalAccessException iae) |
| { |
| throw new NoSuchAlgorithmException(algorithm + ": Illegal Access"); |
| } |
| } |
| |
| |
| /** |
| Gets the provider that the MessageDigest is from. |
| |
| @return the provider the this MessageDigest |
| */ |
| 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 from the |
| specified offset to the specified length. |
| |
| @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 from the array. |
| |
| @param input bytes to update the digest with |
| */ |
| public void update(byte[]input) |
| { |
| engineUpdate(input, 0, input.length); |
| } |
| |
| /** |
| Computes the 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 |
| them. |
| |
| @param buf An array of bytes to store the digest |
| @param offset An offset to start storing the digest 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 |
| update(input) and then digest(); |
| |
| @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 representation of the MessageDigest as a String. |
| |
| @return a string representing the message digest |
| */ |
| 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 true if they are equal, false 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 message digest. |
| */ |
| public void reset() |
| { |
| engineReset(); |
| } |
| |
| /** |
| Gets the name of the algorithm currently used. |
| The names of algorithms are usually SHA-1 or MD5. |
| |
| @return name of algorithm. |
| */ |
| public final String getAlgorithm() |
| { |
| return algorithm; |
| } |
| |
| /** |
| Gets the length of the message digest. |
| The default is zero which means that this message digest |
| does not implement this function. |
| |
| @return length of the message digest |
| */ |
| public final int getDigestLength() |
| { |
| return engineGetDigestLength(); |
| } |
| |
| /** |
| Returns a clone of this class if supported. |
| If it does not then it throws CloneNotSupportedException. |
| The cloning of this class depends on whether the subclass |
| MessageDigestSpi implements Cloneable which contains the |
| actual implementation of the appropriate algorithm. |
| |
| @return clone of this class |
| |
| @exception CloneNotSupportedException this class does not support cloning |
| */ |
| public Object clone() throws CloneNotSupportedException |
| { |
| if (this instanceof Cloneable) |
| return super.clone(); |
| else |
| throw new CloneNotSupportedException(); |
| } |
| |
| 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(); |
| } |
| |
| } |