/* KeyPairGenerator.java --- Key Pair Generator Class 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; import java.security.spec.AlgorithmParameterSpec; /** KeyPairGenerator is the class used to generate key pairs for a security algorithm. The KeyPairGenerator is created with the getInstance() methods. The class is used to generate public and private keys for an algorithm and associate it with algorithm parameters. @author Mark Benvenuto */ public abstract class KeyPairGenerator extends KeyPairGeneratorSpi { Provider provider; private String algorithm; /** Constructs a new KeyPairGenerator @param algorithm the algorithm to use */ protected KeyPairGenerator(String algorithm) { this.algorithm = algorithm; this.provider = null; } /** Returns the name of the algorithm used @return A string with the name of the algorithm */ public String getAlgorithm() { return algorithm; } /** Gets an instance of the KeyPairGenerator class which generates key pairs for the specified algorithm. If the algorithm is not found then, it throws NoSuchAlgorithmException. @param algorithm the name of algorithm to choose @return a AlgorithmParameterGenerator repesenting the desired algorithm @throws NoSuchAlgorithmException if the algorithm is not implemented by providers */ public static KeyPairGenerator 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 KeyPairGenerator class which generates key pairs for the specified algorithm. If the algorithm is not found then, it throws NoSuchAlgorithmException. @param algorithm the name of algorithm to choose @param provider the name of the provider to find the algorithm in @return a AlgorithmParameterGenerator repesenting the desired algorithm @throws NoSuchAlgorithmException if the algorithm is not implemented by the provider @throws NoSuchProviderException if the provider is not found */ public static KeyPairGenerator 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 KeyPairGenerator getInstance(String algorithm, Provider p) throws NoSuchAlgorithmException { // try the name as is String className = p.getProperty("KeyPairGenerator." + algorithm); if (className == null) { // try all uppercase String upper = algorithm.toUpperCase(); className = p.getProperty("KeyPairGenerator." + upper); if (className == null) { // try if it's an alias String alias = p.getProperty("Alg.Alias.KeyPairGenerator." + algorithm); if (alias == null) { // try all-uppercase alias name alias = p.getProperty("Alg.Alias.KeyPairGenerator." + upper); if (alias == null) { // spit the dummy throw new NoSuchAlgorithmException(algorithm); } } className = p.getProperty("KeyPairGenerator." + alias); if (className == null) { throw new NoSuchAlgorithmException(algorithm); } } } return getInstance(className, algorithm, p); } private static KeyPairGenerator getInstance(String classname, String algorithm, Provider provider) throws NoSuchAlgorithmException { try { Object o = Class.forName(classname).newInstance(); KeyPairGenerator kpg; if (o instanceof KeyPairGeneratorSpi) kpg = new DummyKeyPairGenerator((KeyPairGeneratorSpi) o, algorithm); else { kpg = (KeyPairGenerator) o; kpg.algorithm = algorithm; } kpg.provider = provider; return kpg; } catch (ClassNotFoundException cnfe) { throw new NoSuchAlgorithmException("Class not found"); } catch (InstantiationException ie) { throw new NoSuchAlgorithmException("Class instantiation failed"); } catch (IllegalAccessException iae) { throw new NoSuchAlgorithmException("Illegal Access"); } } /** Gets the provider that the class is from. @return the provider of this class */ public final Provider getProvider() { return provider; } /** Initializes the KeyPairGenerator for the specified key size. (Since no source of randomness is specified, a default one is provided.) @param keysize Size of key to generate */ public void initialize(int keysize) { initialize(keysize, new SecureRandom()); } /** Initializes the KeyPairGenerator for the specified key size and specified SecureRandom. @param keysize Size of key to generate @param random SecureRandom to use @since JDK 1.2 */ public void initialize(int keysize, SecureRandom random) { initialize(keysize, random); } /** Initializes the KeyPairGenerator with the specified AlgorithmParameterSpec class. (Since no source of randomness is specified, a default one is provided.) @param params AlgorithmParameterSpec to initialize with @since JDK 1.2 */ public void initialize(AlgorithmParameterSpec params) throws InvalidAlgorithmParameterException { initialize(params, new SecureRandom()); } /** Initializes the KeyPairGenerator with the specified AlgorithmParameterSpec class and specified SecureRandom. @param params AlgorithmParameterSpec to initialize with @param random SecureRandom to use @since JDK 1.2 */ public void initialize(AlgorithmParameterSpec params, SecureRandom random) throws InvalidAlgorithmParameterException { super.initialize(params, random); } /** Generates a KeyPair according the rules for the algorithm. Unless intialized, algorithm defaults will be used. It creates a unique key pair each time. Same as generateKeyPair(); @return a key pair */ public final KeyPair genKeyPair() { try { return getInstance("DSA", "GNU").generateKeyPair(); } catch (Exception e) { System.err.println("genKeyPair failed: " + e); e.printStackTrace(); return null; } } /** Generates a KeyPair according the rules for the algorithm. Unless intialized, algorithm defaults will be used. It creates a unique key pair each time. Same as genKeyPair(); @return a key pair */ public KeyPair generateKeyPair() { return genKeyPair(); } }