diff options
Diffstat (limited to 'libjava/classpath/java/security/KeyPairGenerator.java')
| -rw-r--r-- | libjava/classpath/java/security/KeyPairGenerator.java | 401 |
1 files changed, 401 insertions, 0 deletions
diff --git a/libjava/classpath/java/security/KeyPairGenerator.java b/libjava/classpath/java/security/KeyPairGenerator.java new file mode 100644 index 0000000..e6f926e --- /dev/null +++ b/libjava/classpath/java/security/KeyPairGenerator.java @@ -0,0 +1,401 @@ +/* KeyPairGenerator.java --- Key Pair Generator Class + Copyright (C) 1999, 2002, 2003, 2004 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; + +import java.security.spec.AlgorithmParameterSpec; + +/** + * <p>The <code>KeyPairGenerator</code> class is used to generate pairs of + * public and private keys. Key pair generators are constructed using the + * <code>getInstance()</code> factory methods (static methods that return + * instances of a given class).</p> + * + * <p>A Key pair generator for a particular algorithm creates a public/private + * key pair that can be used with this algorithm. It also associates + * algorithm-specific parameters with each of the generated keys.</p> + * + * <p>There are two ways to generate a key pair: in an algorithm-independent + * manner, and in an algorithm-specific manner. The only difference between the + * two is the initialization of the object:</p> + * + * <ul> + * <li><b>Algorithm-Independent Initialization</b><br/> + * All key pair generators share the concepts of a <i>keysize</i> and a + * <i>source of randomness</i>. The <i>keysize</i> is interpreted differently + * for different algorithms (e.g., in the case of the <i>DSA</i> algorithm, + * the <i>keysize</i> corresponds to the length of the modulus). There is an + * <code>initialize()</code> method in this <code>KeyPairGenerator</code> + * class that takes these two universally shared types of arguments. There + * is also one that takes just a <i>keysize</i> argument, and uses the + * {@link SecureRandom} implementation of the highest-priority installed + * provider as the <i>source of randomness</i>. (If none of the installed + * providers supply an implementation of {@link SecureRandom}, a + * system-provided source of randomness is used.) + * + * <p>Since no other parameters are specified when you call the above + * algorithm-independent initialize methods, it is up to the provider what + * to do about the algorithm-specific parameters (if any) to be associated + * with each of the keys.</p> + * + * <p>If the algorithm is the <i>DSA</i> algorithm, and the <i>keysize</i> + * (modulus size) is <code>512</code>, <code>768</code>, or <code>1024</code>, + * then the <b>GNU</b> provider uses a set of precomputed values for the + * <code>p</code>, <code>q</code>, and <code>g</code> parameters. If the + * <i>modulus size</i> is not one of the above values, the <b>GNU</b> + * provider creates a new set of parameters. Other providers might have + * precomputed parameter sets for more than just the three modulus sizes + * mentioned above. Still others might not have a list of precomputed + * parameters at all and instead always create new parameter sets.</p></li> + * <li><b>Algorithm-Specific Initialization</b><br/> + * For situations where a set of algorithm-specific parameters already + * exists (e.g., so-called <i>community parameters</i> in <i>DSA</i>), there + * are two initialize methods that have an {@link AlgorithmParameterSpec} + * argument. One also has a {@link SecureRandom} argument, while the the + * other uses the {@link SecureRandom} implementation of the highest-priority + * installed provider as the source of randomness. (If none of the installed + * providers supply an implementation of {@link SecureRandom}, a + * system-provided source of randomness is used.)</li> + * </ul> + * + * <p>In case the client does not explicitly initialize the + * <code>KeyPairGenerator</code> (via a call to an initialize method), each + * provider must supply (and document) a default initialization. For example, + * the <b>GNU</b> provider uses a default modulus size (keysize) of + * <code>1024</code> bits.</p> + * + * <p>Note that this class is abstract and extends from {@link + * KeyPairGeneratorSpi} for historical reasons. Application developers should + * only take notice of the methods defined in this <code>KeyPairGenerator</code> + * class; all the methods in the superclass are intended for cryptographic + * service providers who wish to supply their own implementations of key pair + * generators.</p> + * + * @see Signature + * @see KeyPair + * @see AlgorithmParameterSpec + * @author Mark Benvenuto + * @author Casey Marshall + */ +public abstract class KeyPairGenerator extends KeyPairGeneratorSpi +{ + /** The service name for key pair generators. */ + private static final String KEY_PAIR_GENERATOR = "KeyPairGenerator"; + + Provider provider; + private String algorithm; + + /** + * Creates a <code>KeyPairGenerator</code> object for the specified + * algorithm. + * + * @param algorithm the standard string name of the algorithm. + * See Appendix A in the Java Cryptography Architecture API + * Specification & Reference for information about standard + * algorithm names. + */ + protected KeyPairGenerator(String algorithm) + { + this.algorithm = algorithm; + this.provider = null; + } + + /** + * Returns the standard name of the algorithm for this key pair generator. + * See Appendix A in the Java Cryptography Architecture API Specification + * & Reference for information about standard algorithm names. + * + * @return the standard string name of the algorithm. + */ + public String getAlgorithm() + { + return algorithm; + } + + /** + * Generates a <code>KeyPairGenerator</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>KeyPairGenerator</code> containing that implementation is returned. + * If the algorithm is not available in the default package, other packages + * are searched. + * + * @param algorithm the standard string name of the algorithm. See Appendix A + * in the Java Cryptography Architecture API Specification & Reference for + * information about standard algorithm names. + * @return the new <code>KeyPairGenerator</code> object. + * @throws NoSuchAlgorithmException if the algorithm is not available in the + * environment. + */ + 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 e) + { + // Ignored. + } + } + + throw new NoSuchAlgorithmException(algorithm); + } + + /** + * Generates a <code>KeyPairGenerator</code> object implementing the + * specified algorithm, as supplied from the specified provider, if + * such an algorithm is available from the provider. + * + * @param algorithm the standard string name of the algorithm. See + * Appendix A in the Java Cryptography Architecture API Specification + * & Reference for information about standard algorithm names. + * @param provider the string name of the provider. + * @return the new <code>KeyPairGenerator</code> object. + * @throws NoSuchAlgorithmException if the algorithm is not available + * from the provider. + * @throws NoSuchProviderException if the provider is not available in the + * environment. + * @throws IllegalArgumentException if the provider name is <code>null</code> + * or empty. + * @see Provider + */ + 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); + } + + /** + * Generates a <code>KeyPairGenerator</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 standard string name of the algorithm. See Appendix A + * in the Java Cryptography Architecture API Specification & Reference for + * information about standard algorithm names. + * @param provider the provider. + * @return the new <code>KeyPairGenerator</code> object. + * @throws NoSuchAlgorithmException if the <code>algorithm</code> is not + * available from the <code>provider</code>. + * @throws IllegalArgumentException if the <code>provider</code> is + * <code>null</code>. + * @since 1.4 + * @see Provider + */ + public static KeyPairGenerator getInstance(String algorithm, + Provider provider) + throws NoSuchAlgorithmException + { + if (provider == null) + throw new IllegalArgumentException("Illegal provider"); + + Object o = null; + try + { + o = Engine.getInstance(KEY_PAIR_GENERATOR, algorithm, provider); + } + catch (java.lang.reflect.InvocationTargetException ite) + { + throw new NoSuchAlgorithmException(algorithm); + } + + KeyPairGenerator result = null; + if (o instanceof KeyPairGeneratorSpi) + { + result = new DummyKeyPairGenerator((KeyPairGeneratorSpi) o, algorithm); + } + else if (o instanceof KeyPairGenerator) + { + result = (KeyPairGenerator) o; + result.algorithm = algorithm; + } + result.provider = provider; + return result; + } + + /** + * Returns the provider of this key pair generator object. + * + * @return the provider of this key pair generator object. + */ + public final Provider getProvider() + { + return provider; + } + + /** + * Initializes the key pair generator for a certain keysize using a default + * parameter set and the {@link SecureRandom} implementation of the + * highest-priority installed provider as the source of randomness. (If none + * of the installed providers supply an implementation of {@link SecureRandom}, + * a system-provided source of randomness is used.) + * + * @param keysize the keysize. This is an algorithm-specific metric, such as + * modulus length, specified in number of bits. + * @throws InvalidParameterException if the keysize is not supported by this + * <code>KeyPairGenerator</code> object. + */ + public void initialize(int keysize) + { + initialize(keysize, new SecureRandom()); + } + + /** + * Initializes the key pair generator for a certain keysize with the given + * source of randomness (and a default parameter set). + * + * @param keysize the keysize. This is an algorithm-specific metric, such as + * modulus length, specified in number of bits. + * @param random the source of randomness. + * @throws InvalidParameterException if the <code>keysize</code> is not + * supported by this <code>KeyPairGenerator</code> object. + * @since 1.2 + */ + public void initialize(int keysize, SecureRandom random) + { + initialize(keysize, random); + } + + /** + * <p>Initializes the key pair generator using the specified parameter set and + * the {@link SecureRandom} implementation of the highest-priority installed + * provider as the source of randomness. (If none of the installed providers + * supply an implementation of {@link SecureRandom}, a system-provided source + * of randomness is used.)</p> + * + * <p>This concrete method has been added to this previously-defined abstract + * class. This method calls the + * {@link KeyPairGeneratorSpi#initialize(AlgorithmParameterSpec, SecureRandom)} + * initialize method, passing it <code>params</code> and a source of + * randomness (obtained from the highest-priority installed provider or + * system-provided if none of the installed providers supply one). That + * initialize method always throws an {@link UnsupportedOperationException} + * if it is not overridden by the provider.</p> + * + * @param params the parameter set used to generate the keys. + * @throws InvalidAlgorithmParameterException if the given parameters are + * inappropriate for this key pair generator. + * @since 1.2 + */ + public void initialize(AlgorithmParameterSpec params) + throws InvalidAlgorithmParameterException + { + initialize(params, new SecureRandom()); + } + + /** + * <p>Initializes the key pair generator with the given parameter set and + * source of randomness.</p> + * + * <p>This concrete method has been added to this previously-defined abstract + * class. This method calls the + * {@link KeyPairGeneratorSpi#initialize(AlgorithmParameterSpec, SecureRandom)} + * initialize method, passing it <code>params</code> and <code>random</code>. + * That initialize method always throws an {@link UnsupportedOperationException} + * if it is not overridden by the provider.</p> + * + * @param params the parameter set used to generate the keys. + * @param random the source of randomness. + * @throws InvalidAlgorithmParameterException if the given parameters are + * inappropriate for this key pair generator. + * @since 1.2 + */ + public void initialize(AlgorithmParameterSpec params, SecureRandom random) + throws InvalidAlgorithmParameterException + { + super.initialize(params, random); + } + + /** + * <p>Generates a key pair.</p> + * + * <p>If this <code>KeyPairGenerator</code> has not been initialized + * explicitly, provider-specific defaults will be used for the size and other + * (algorithm-specific) values of the generated keys.</p> + * + * <p>This will generate a new key pair every time it is called.</p> + * + * <p>This method is functionally equivalent to {@link #generateKeyPair()}.</p> + * + * @return the generated key pair. + * @since 1.2 + */ + public final KeyPair genKeyPair() + { + try + { + return getInstance("DSA", "GNU").generateKeyPair(); + } + catch (Exception e) + { + System.err.println("genKeyPair failed: " + e); + e.printStackTrace(); + return null; + } + } + + /** + * <p>Generates a key pair.</p> + * + * <p>If this <code>KeyPairGenerator</code> has not been initialized + * explicitly, provider-specific defaults will be used for the size and other + * (algorithm-specific) values of the generated keys.</p> + * + * <p>This will generate a new key pair every time it is called.</p> + * + * <p>This method is functionally equivalent to {@link #genKeyPair()}.</p> + * + * @return the generated key pair. + */ + public KeyPair generateKeyPair() + { + return genKeyPair(); + } +} |