257 lines
7.0 KiB
Java
257 lines
7.0 KiB
Java
/* KeyPairGenerator.java --- Key Pair Generator Class
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Copyright (C) 1999 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., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.security;
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import java.security.spec.AlgorithmParameterSpec;
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/**
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KeyPairGenerator is the class used to generate key pairs
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for a security algorithm.
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The KeyPairGenerator is created with the getInstance()
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methods. The class is used to generate public and private
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keys for an algorithm and associate it with
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algorithm parameters.
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@author Mark Benvenuto
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*/
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public abstract class KeyPairGenerator extends KeyPairGeneratorSpi
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{
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private Provider provider;
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private String algorithm;
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/**
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Constructs a new KeyPairGenerator
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@param algorithm the algorithm to use
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*/
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protected KeyPairGenerator(String algorithm)
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{
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this.algorithm = algorithm;
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this.provider = null;
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}
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/**
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Returns the name of the algorithm used
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@return A string with the name of the algorithm
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*/
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public String getAlgorithm()
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{
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return algorithm;
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}
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/**
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Gets an instance of the KeyPairGenerator class
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which generates key pairs for the specified algorithm.
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If the algorithm is not found then, it throws NoSuchAlgorithmException.
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@param algorithm the name of algorithm to choose
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@return a AlgorithmParameterGenerator repesenting the desired algorithm
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@throws NoSuchAlgorithmException if the algorithm is not implemented by providers
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*/
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public static KeyPairGenerator getInstance(String algorithm) throws
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NoSuchAlgorithmException
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{
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Provider[] p = Security.getProviders();
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String name = "KeyPairGenerator." + algorithm;
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for (int i = 0; i < p.length; i++)
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{
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String classname = p[i].getProperty(name);
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if (classname != null)
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return getInstance(classname, algorithm, p[i]);
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}
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throw new NoSuchAlgorithmException(algorithm);
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}
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/**
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Gets an instance of the KeyPairGenerator class
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which generates key pairs for the specified algorithm.
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If the algorithm is not found then, it throws NoSuchAlgorithmException.
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@param algorithm the name of algorithm to choose
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@param provider the name of the provider to find the algorithm in
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@return a AlgorithmParameterGenerator repesenting the desired algorithm
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@throws NoSuchAlgorithmException if the algorithm is not implemented by the provider
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@throws NoSuchProviderException if the provider is not found
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*/
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public static KeyPairGenerator getInstance(String algorithm, String provider)
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throws NoSuchAlgorithmException, NoSuchProviderException
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{
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Provider p = Security.getProvider(provider);
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if (p == null)
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throw new NoSuchProviderException();
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return getInstance(p.getProperty("KeyPairGenerator." + algorithm),
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algorithm, p);
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}
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private static KeyPairGenerator getInstance(String classname,
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String algorithm,
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Provider provider)
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throws NoSuchAlgorithmException
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{
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try
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{
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Object o = Class.forName(classname).newInstance();
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KeyPairGenerator kpg;
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if (o instanceof KeyPairGeneratorSpi)
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kpg =
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(KeyPairGenerator) (new
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DummyKeyPairGenerator((KeyPairGeneratorSpi) o,
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algorithm));
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else
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{
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kpg = (KeyPairGenerator) o;
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kpg.algorithm = algorithm;
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}
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kpg.provider = provider;
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return kpg;
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}
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catch (ClassNotFoundException cnfe)
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{
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throw new NoSuchAlgorithmException("Class not found");
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}
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catch (InstantiationException ie)
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{
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throw new NoSuchAlgorithmException("Class instantiation failed");
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}
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catch (IllegalAccessException iae)
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{
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throw new NoSuchAlgorithmException("Illegal Access");
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}
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}
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/**
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Gets the provider that the class is from.
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@return the provider of this class
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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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Initializes the KeyPairGenerator for the specified key size.
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(Since no source of randomness is specified, a default one is
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provided.)
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@param keysize Size of key to generate
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*/
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public void initialize(int keysize)
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{
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initialize(keysize, new SecureRandom());
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}
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/**
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Initializes the KeyPairGenerator for the specified key size
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and specified SecureRandom.
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@param keysize Size of key to generate
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@param random SecureRandom to use
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@since JDK 1.2
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*/
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public void initialize(int keysize, SecureRandom random)
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{
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initialize(keysize, random);
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}
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/**
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Initializes the KeyPairGenerator with the specified
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AlgorithmParameterSpec class.
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(Since no source of randomness is specified, a default one is
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provided.)
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@param params AlgorithmParameterSpec to initialize with
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@since JDK 1.2
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*/
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public void initialize(AlgorithmParameterSpec params)
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throws InvalidAlgorithmParameterException
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{
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initialize(params, new SecureRandom());
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}
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/**
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Initializes the KeyPairGenerator with the specified
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AlgorithmParameterSpec class and specified SecureRandom.
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@param params AlgorithmParameterSpec to initialize with
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@param random SecureRandom to use
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@since JDK 1.2
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*/
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public void initialize(AlgorithmParameterSpec params, SecureRandom random)
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throws InvalidAlgorithmParameterException
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{
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super.initialize(params, random);
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}
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/**
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Generates a KeyPair according the rules for the algorithm.
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Unless intialized, algorithm defaults will be used. It
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creates a unique key pair each time.
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Same as generateKeyPair();
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@return a key pair
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*/
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public final KeyPair genKeyPair()
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{
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try
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{
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return getInstance("DSA", "GNU").generateKeyPair();
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}
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catch (Exception e)
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{
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System.err.println("genKeyPair failed: " + e);
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e.printStackTrace();
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return null;
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}
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}
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/**
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Generates a KeyPair according the rules for the algorithm.
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Unless intialized, algorithm defaults will be used. It
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creates a unique key pair each time.
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Same as genKeyPair();
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@return a key pair
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*/
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public KeyPair generateKeyPair()
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{
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return genKeyPair();
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}
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}
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