294 lines
9.4 KiB
Java
294 lines
9.4 KiB
Java
/* KeyGenerator.java -- Interface to a symmetric key generator.
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Copyright (C) 2004 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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02110-1301 USA.
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Linking this library statically or dynamically with other modules is
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making a combined work based on this library. Thus, the terms and
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conditions of the GNU General Public License cover the whole
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combination.
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As a special exception, the copyright holders of this library give you
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permission to link this library with independent modules to produce an
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executable, regardless of the license terms of these independent
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modules, and to copy and distribute the resulting executable under
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terms of your choice, provided that you also meet, for each linked
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independent module, the terms and conditions of the license of that
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module. An independent module is a module which is not derived from
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or based on this library. If you modify this library, you may extend
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this exception to your version of the library, but you are not
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obligated to do so. If you do not wish to do so, delete this
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exception statement from your version. */
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package javax.crypto;
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import gnu.java.security.Engine;
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import java.lang.reflect.InvocationTargetException;
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import java.security.InvalidAlgorithmParameterException;
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import java.security.NoSuchAlgorithmException;
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import java.security.NoSuchProviderException;
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import java.security.Provider;
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import java.security.SecureRandom;
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import java.security.Security;
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import java.security.spec.AlgorithmParameterSpec;
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/**
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* A generic producer of keys for symmetric cryptography. The keys
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* returned may be simple wrappers around byte arrays, or, if the
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* target cipher requires them, more complex objects.
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*
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* @author Casey Marshall (csm@gnu.org)
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* @since 1.4
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* @see Cipher
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* @see Mac
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*/
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public class KeyGenerator
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{
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// Constants and fields.
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// ------------------------------------------------------------------------
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private static final String SERVICE = "KeyGenerator";
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/** The underlying generator implementation. */
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private KeyGeneratorSpi kgSpi;
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/** The provider of the implementation. */
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private Provider provider;
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/** The name of the algorithm. */
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private String algorithm;
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// Constructor.
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// ------------------------------------------------------------------------
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/**
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* Create a new key generator.
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*
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* @param kgSpi The underlying generator.
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* @param provider The provider of this implementation.
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* @param algorithm The algorithm's name.
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*/
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protected KeyGenerator(KeyGeneratorSpi kgSpi, Provider provider,
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String algorithm)
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{
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this.kgSpi = kgSpi;
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this.provider = provider;
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this.algorithm = algorithm;
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}
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/**
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* Create a new key generator, returning the first available implementation.
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*
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* @param algorithm The generator algorithm name.
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* @throws NoSuchAlgorithmException If the specified algorithm does not exist.
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* @throws IllegalArgumentException if <code>algorithm</code> is
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* <code>null</code> or is an empty string.
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*/
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public static final KeyGenerator getInstance(String algorithm)
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throws NoSuchAlgorithmException
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{
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Provider[] p = Security.getProviders();
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NoSuchAlgorithmException lastException = null;
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for (int i = 0; i < p.length; i++)
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try
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{
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return getInstance(algorithm, p[i]);
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}
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catch (NoSuchAlgorithmException x)
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{
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lastException = x;
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}
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if (lastException != null)
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throw lastException;
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throw new NoSuchAlgorithmException(algorithm);
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}
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/**
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* Create a new key generator from the named provider.
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*
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* @param algorithm The generator algorithm name.
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* @param provider The name of the provider to use.
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* @return An appropriate key generator, if found.
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* @throws NoSuchAlgorithmException If the specified algorithm is not
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* implemented by the named provider.
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* @throws NoSuchProviderException If the named provider does not exist.
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* @throws IllegalArgumentException if either <code>algorithm</code> or
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* <code>provider</code> is <code>null</code>, or if
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* <code>algorithm</code> is an empty string.
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*/
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public static final KeyGenerator getInstance(String algorithm, String provider)
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throws NoSuchAlgorithmException, NoSuchProviderException
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{
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if (provider == null)
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throw new IllegalArgumentException("provider MUST NOT be null");
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Provider p = Security.getProvider(provider);
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if (p == null)
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throw new NoSuchProviderException(provider);
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return getInstance(algorithm, p);
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}
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/**
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* Create a new key generator from the supplied provider.
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*
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* @param algorithm The generator algorithm name.
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* @param provider The provider to use.
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* @return An appropriate key generator, if found.
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* @throws NoSuchAlgorithmException If the specified algorithm is not
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* implemented by the provider.
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* @throws IllegalArgumentException if either <code>algorithm</code> or
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* <code>provider</code> is <code>null</code>, or if
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* <code>algorithm</code> is an empty string.
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*/
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public static final KeyGenerator getInstance(String algorithm,
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Provider provider)
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throws NoSuchAlgorithmException
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{
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StringBuilder sb = new StringBuilder("KeyGenerator algorithm [")
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.append(algorithm).append("] from provider[")
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.append(provider).append("] could not be created");
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Throwable cause;
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try
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{
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Object spi = Engine.getInstance(SERVICE, algorithm, provider);
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KeyGenerator instance = new KeyGenerator((KeyGeneratorSpi) spi,
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provider,
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algorithm);
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instance.init(new SecureRandom());
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return instance;
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}
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catch (InvocationTargetException x)
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{
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cause = x.getCause();
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if (cause instanceof NoSuchAlgorithmException)
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throw (NoSuchAlgorithmException) cause;
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if (cause == null)
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cause = x;
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}
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catch (ClassCastException x)
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{
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cause = x;
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}
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NoSuchAlgorithmException x = new NoSuchAlgorithmException(sb.toString());
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x.initCause(cause);
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throw x;
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}
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/**
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* Generate a key.
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*
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* @return The new key.
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*/
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public final SecretKey generateKey()
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{
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return kgSpi.engineGenerateKey();
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}
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/**
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* Return the name of this key generator.
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*
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* @return The algorithm name.
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*/
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public final String getAlgorithm()
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{
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return algorithm;
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}
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/**
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* Return the provider of the underlying implementation.
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*
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* @return The provider.
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*/
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public final Provider getProvider()
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{
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return provider;
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}
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/**
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* Initialize this key generator with a set of parameters; the
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* highest-priority {@link java.security.SecureRandom} implementation
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* will be used.
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*
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* @param params The algorithm parameters.
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* @throws java.security.InvalidAlgorithmParameterException If the
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* supplied parameters are inapproprate.
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*/
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public final void init(AlgorithmParameterSpec params)
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throws InvalidAlgorithmParameterException
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{
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init(params, new SecureRandom());
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}
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/**
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* Initialize this key generator with a set of parameters and a source
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* of randomness.
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*
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* @param params The algorithm parameters.
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* @param random The source of randomness.
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* @throws java.security.InvalidAlgorithmParameterException If the
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* supplied parameters are inapproprate.
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*/
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public final void init(AlgorithmParameterSpec params, SecureRandom random)
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throws InvalidAlgorithmParameterException
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{
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kgSpi.engineInit(params, random);
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}
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/**
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* Initialize this key generator with a key size (in bits); the
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* highest-priority {@link java.security.SecureRandom} implementation
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* will be used.
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*
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* @param keySize The target key size, in bits.
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* @throws java.security.InvalidParameterException If the
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* key size is unsupported.
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*/
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public final void init(int keySize)
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{
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init(keySize, new SecureRandom());
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}
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/**
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* Initialize this key generator with a key size (in bits) and a
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* source of randomness.
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*
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* @param keySize The target key size, in bits.
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* @param random The source of randomness.
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* @throws java.security.InvalidAlgorithmParameterException If the
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* key size is unsupported.
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*/
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public final void init(int keySize, SecureRandom random)
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{
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kgSpi.engineInit(keySize, random);
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}
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/**
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* Initialize this key generator with a source of randomness. The
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* implementation-specific default parameters (such as key size) will
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* be used.
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*
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* @param random The source of randomness.
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*/
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public final void init(SecureRandom random)
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{
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kgSpi.engineInit(random);
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}
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}
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