349 lines
9.5 KiB
Java
349 lines
9.5 KiB
Java
/* SecureRandom.java --- Secure Random class implmentation
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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.io.Serializable;
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import java.util.Random;
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import java.util.Enumeration;
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/**
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SecureRandom is the class interface for using SecureRandom
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providers. It provides an interface to the SecureRandomSpi
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engine so that programmers can generate pseudo-random numbers.
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@author Mark Benvenuto <ivymccough@worldnet.att.net>
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*/
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public class SecureRandom extends Random
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{
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//Serialized Field
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long counter = 0; //Serialized
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MessageDigest digest = null;
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Provider provider = null;
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byte[] randomBytes = null; //Always null
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int randomBytesUsed = 0;
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SecureRandomSpi secureRandomSpi = null;
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byte[] state = null;
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/**
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Default constructor for SecureRandom. It constructs a
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new SecureRandom by instantating the first SecureRandom
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algorithm in the default security provier.
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It is not seeded and should be seeded using setseed or else
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on the first call to getnextBytes it will force a seed.
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It is maintained for backwards compatability and programs
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should use getInstance.
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*/
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public SecureRandom()
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{
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Provider p[] = Security.getProviders();
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//Format of Key: SecureRandom.algname
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String key;
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String classname = null;
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int i, flag = 0;
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Enumeration e;
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for (i = 0; i < p.length; i++)
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{
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e = p[i].propertyNames();
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while (e.hasMoreElements())
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{
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key = (String) e.nextElement();
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if (key.startsWith("SecureRandom."))
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if ((classname = p[i].getProperty(key)) != null)
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break;
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}
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if (classname != null)
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break;
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}
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//if( classname == null)
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// throw new NoSuchAlgorithmException();
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try
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{
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this.secureRandomSpi =
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(SecureRandomSpi) Class.forName(classname).newInstance();
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//s.algorithm = algorithm;
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this.provider = p[i];
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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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A constructor for SecureRandom. It constructs a new
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SecureRandom by instantating the first SecureRandom algorithm
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in the default security provier.
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It is seeded with the passed function and is useful if the user
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has access to hardware random device (like a radiation detector).
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It is maintained for backwards compatability and programs
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should use getInstance.
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@param seed Seed bytes for class
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*/
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public SecureRandom(byte[] seed)
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{
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this();
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setSeed(seed);
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}
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/**
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A constructor for SecureRandom. It constructs a new
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SecureRandom using the specified SecureRandomSpi from
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the specified security provier.
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@param secureRandomSpi A SecureRandomSpi class
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@param provider A Provider class
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*/
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protected SecureRandom(SecureRandomSpi secureRandomSpi, Provider provider)
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{
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this.secureRandomSpi = secureRandomSpi;
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this.provider = provider;
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}
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/**
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Returns an instance of a SecureRandom. It creates the class
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for the specified algorithm if it exists from a provider.
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@param algorithm A SecureRandom algorithm to use
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@return Returns a new SecureRandom implmenting the chosen algorithm
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@throws NoSuchAlgorithmException if the algorithm cannot be found
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*/
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public static SecureRandom 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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//Format of Key: SecureRandom.algname
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StringBuffer key = new StringBuffer("SecureRandom.");
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key.append(algorithm);
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String classname = null;
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int i;
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for (i = 0; i < p.length; i++)
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{
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if ((classname = p[i].getProperty(key.toString())) != null)
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break;
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}
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if (classname == null)
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throw new NoSuchAlgorithmException();
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try
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{
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return new SecureRandom((SecureRandomSpi) Class.forName(classname).
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newInstance(), p[i]);
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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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Returns an instance of a SecureRandom. It creates the class
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for the specified algorithm from the specified provider.
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@param algorithm A SecureRandom algorithm to use
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@param provider A security provider to use
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@return Returns a new SecureRandom implmenting the chosen algorithm
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@throws NoSuchAlgorithmException if the algorithm cannot be found
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@throws NoSuchProviderException if the provider cannot be found
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*/
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public static SecureRandom getInstance(String algorithm,
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String provider) throws
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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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//Format of Key: SecureRandom.algName
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StringBuffer key = new StringBuffer("SecureRandom.");
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key.append(algorithm);
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String classname = p.getProperty(key.toString());
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if (classname == null)
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throw new NoSuchAlgorithmException();
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try
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{
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return new SecureRandom((SecureRandomSpi) Class.forName(classname).
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newInstance(), p);
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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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Returns the provider being used by the current SecureRandom class.
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@return The provider from which this SecureRandom was attained
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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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Seeds the SecureRandom. The class is re-seeded for each call and
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each seed builds on the previous seed so as not to weaken security.
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@param seed seed bytes to seed with
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*/
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public void setSeed(byte[] seed)
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{
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secureRandomSpi.engineSetSeed(seed);
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}
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/**
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Seeds the SecureRandom. The class is re-seeded for each call and
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each seed builds on the previous seed so as not to weaken security.
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@param seed 8 seed bytes to seed with
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*/
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public void setSeed(long seed)
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{
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byte tmp[] = { (byte) (0xff & (seed >> 56)), (byte) (0xff & (seed >> 48)),
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(byte) (0xff & (seed >> 40)), (byte) (0xff & (seed >> 32)),
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(byte) (0xff & (seed >> 24)), (byte) (0xff & (seed >> 16)),
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(byte) (0xff & (seed >> 8)), (byte) (0xff & seed)
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};
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secureRandomSpi.engineSetSeed(tmp);
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}
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/**
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Generates a user specified number of bytes. This function
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is the basis for all the random functions.
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@param bytes array to store generated bytes in
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*/
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public void nextBytes(byte[] bytes)
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{
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randomBytesUsed += bytes.length;
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counter++;
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secureRandomSpi.engineNextBytes(bytes);
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}
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/**
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Generates an integer containing the user specified
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number of random bits. It is right justified and padded
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with zeros.
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@param numBits number of random bits to get, 0 <= numBits <= 32;
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@return the random bits
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*/
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protected final int next(int numBits)
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{
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if (numBits == 0)
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return 0;
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byte tmp[] = new byte[numBits / 8 + (1 * (numBits % 8))];
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secureRandomSpi.engineNextBytes(tmp);
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randomBytesUsed += tmp.length;
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counter++;
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int ret = 0;
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for (int i = 0; i < tmp.length; i++)
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ret |= tmp[i] << (8 * i);
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return ret;
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}
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/**
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Returns the given number of seed bytes. This method is
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maintained only for backwards capability.
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@param numBytes number of seed bytes to get
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@return an array containing the seed bytes
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*/
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public static byte[] getSeed(int numBytes)
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{
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byte tmp[] = new byte[numBytes];
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new Random().nextBytes(tmp);
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return tmp;
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//return secureRandomSpi.engineGenerateSeed( numBytes );
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}
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/**
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Returns the specified number of seed bytes.
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@param numBytes number of seed bytes to get
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@return an array containing the seed bytes
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*/
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public byte[] generateSeed(int numBytes)
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{
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return secureRandomSpi.engineGenerateSeed(numBytes);
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}
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}
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