| /* SecureRandom.java --- Secure Random class implementation |
| Copyright (C) 1999, 2001, 2002, 2003, 2005 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 gnu.java.security.Engine; |
| |
| import java.util.Enumeration; |
| import java.util.Random; |
| |
| /** |
| * An interface to a cryptographically secure pseudo-random number |
| * generator (PRNG). Random (or at least unguessable) numbers are used |
| * in all areas of security and cryptography, from the generation of |
| * keys and initialization vectors to the generation of random padding |
| * bytes. |
| * |
| * @author Mark Benvenuto (ivymccough@worldnet.att.net) |
| * @author Casey Marshall |
| */ |
| public class SecureRandom extends Random |
| { |
| |
| // Constants and fields. |
| // ------------------------------------------------------------------------ |
| |
| /** Service name for PRNGs. */ |
| private static final String SECURE_RANDOM = "SecureRandom"; |
| |
| private static final long serialVersionUID = 4940670005562187L; |
| |
| //Serialized Field |
| long counter = 0; //Serialized |
| Provider provider = null; |
| byte[] randomBytes = null; //Always null |
| int randomBytesUsed = 0; |
| SecureRandomSpi secureRandomSpi = null; |
| byte[] state = null; |
| |
| // Constructors. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| Default constructor for SecureRandom. It constructs a |
| new SecureRandom by instantating the first SecureRandom |
| algorithm in the default security provier. |
| |
| It is not seeded and should be seeded using setSeed or else |
| on the first call to getnextBytes it will force a seed. |
| |
| It is maintained for backwards compatibility and programs |
| should use {@link #getInstance(java.lang.String)}. |
| */ |
| public SecureRandom() |
| { |
| Provider[] p = Security.getProviders(); |
| |
| //Format of Key: SecureRandom.algname |
| String key; |
| |
| String classname = null; |
| int i; |
| Enumeration e; |
| for (i = 0; i < p.length; i++) |
| { |
| e = p[i].propertyNames(); |
| while (e.hasMoreElements()) |
| { |
| key = (String) e.nextElement(); |
| if (key.startsWith("SECURERANDOM.")) |
| { |
| if ((classname = p[i].getProperty(key)) != null) |
| { |
| try |
| { |
| secureRandomSpi = (SecureRandomSpi) Class. |
| forName(classname).newInstance(); |
| provider = p[i]; |
| return; |
| } |
| catch (ThreadDeath death) |
| { |
| throw death; |
| } |
| catch (Throwable t) |
| { |
| // Ignore. |
| } |
| } |
| } |
| } |
| } |
| |
| // Nothing found. Fall back to SHA1PRNG |
| secureRandomSpi = new gnu.java.security.provider.SHA1PRNG(); |
| } |
| |
| /** |
| A constructor for SecureRandom. It constructs a new |
| SecureRandom by instantating the first SecureRandom algorithm |
| in the default security provier. |
| |
| It is seeded with the passed function and is useful if the user |
| has access to hardware random device (like a radiation detector). |
| |
| It is maintained for backwards compatibility and programs |
| should use getInstance. |
| |
| @param seed Seed bytes for class |
| */ |
| public SecureRandom(byte[] seed) |
| { |
| this(); |
| setSeed(seed); |
| } |
| |
| /** |
| A constructor for SecureRandom. It constructs a new |
| SecureRandom using the specified SecureRandomSpi from |
| the specified security provier. |
| |
| @param secureRandomSpi A SecureRandomSpi class |
| @param provider A Provider class |
| */ |
| protected SecureRandom(SecureRandomSpi secureRandomSpi, Provider provider) |
| { |
| this.secureRandomSpi = secureRandomSpi; |
| this.provider = provider; |
| } |
| |
| // Class methods. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| * Returns an instance of a SecureRandom. It creates the class from |
| * the first provider that implements it. |
| * |
| * @param algorithm The algorithm name. |
| * @return A new SecureRandom implementing the given algorithm. |
| * @throws NoSuchAlgorithmException If no installed provider implements |
| * the given algorithm. |
| */ |
| public static SecureRandom 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) |
| { |
| // Ignore. |
| } |
| } |
| |
| // None found. |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| |
| /** |
| * Returns an instance of a SecureRandom. It creates the class |
| * for the specified algorithm from the named provider. |
| * |
| * @param algorithm The algorithm name. |
| * @param provider The provider name. |
| * @return A new SecureRandom implementing the chosen algorithm. |
| * @throws NoSuchAlgorithmException If the named provider does not implement |
| * the algorithm, or if the implementation cannot be |
| * instantiated. |
| * @throws NoSuchProviderException If no provider named |
| * <code>provider</code> is currently installed. |
| * @throws IllegalArgumentException If <code>provider</code> is null |
| * or is empty. |
| */ |
| public static SecureRandom getInstance(String algorithm, String provider) |
| throws NoSuchAlgorithmException, NoSuchProviderException |
| { |
| if (provider == null || provider.length() == 0) |
| throw new IllegalArgumentException("Illegal provider"); |
| |
| Provider p = Security.getProvider(provider); |
| if (p == null) |
| throw new NoSuchProviderException(provider); |
| |
| return getInstance(algorithm, p); |
| } |
| |
| /** |
| * Returns an instance of a SecureRandom. It creates the class for |
| * the specified algorithm from the given provider. |
| * |
| * @param algorithm The SecureRandom algorithm to create. |
| * @param provider The provider to get the instance from. |
| * @throws NoSuchAlgorithmException If the algorithm cannot be found, or |
| * if the class cannot be instantiated. |
| * @throws IllegalArgumentException If <code>provider</code> is null. |
| */ |
| public static SecureRandom getInstance(String algorithm, Provider provider) |
| throws NoSuchAlgorithmException |
| { |
| if (provider == null) |
| throw new IllegalArgumentException("Illegal provider"); |
| try |
| { |
| return new SecureRandom((SecureRandomSpi) |
| Engine.getInstance(SECURE_RANDOM, algorithm, provider), |
| provider); |
| } |
| catch (java.lang.reflect.InvocationTargetException ite) |
| { |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| catch (ClassCastException cce) |
| { |
| throw new NoSuchAlgorithmException(algorithm); |
| } |
| } |
| |
| // Instance methods. |
| // ------------------------------------------------------------------------ |
| |
| /** |
| Returns the provider being used by the current SecureRandom class. |
| |
| @return The provider from which this SecureRandom was attained |
| */ |
| public final Provider getProvider() |
| { |
| return provider; |
| } |
| |
| /** |
| Seeds the SecureRandom. The class is re-seeded for each call and |
| each seed builds on the previous seed so as not to weaken security. |
| |
| @param seed seed bytes to seed with |
| */ |
| public void setSeed(byte[] seed) |
| { |
| secureRandomSpi.engineSetSeed(seed); |
| } |
| |
| /** |
| Seeds the SecureRandom. The class is re-seeded for each call and |
| each seed builds on the previous seed so as not to weaken security. |
| |
| @param seed 8 seed bytes to seed with |
| */ |
| public void setSeed(long seed) |
| { |
| // This particular setSeed will be called by Random.Random(), via |
| // our own constructor, before secureRandomSpi is initialized. In |
| // this case we can't call a method on secureRandomSpi, and we |
| // definitely don't want to throw a NullPointerException. |
| // Therefore we test. |
| if (secureRandomSpi != null) |
| { |
| byte[] tmp = { (byte) (0xff & (seed >> 56)), |
| (byte) (0xff & (seed >> 48)), |
| (byte) (0xff & (seed >> 40)), |
| (byte) (0xff & (seed >> 32)), |
| (byte) (0xff & (seed >> 24)), |
| (byte) (0xff & (seed >> 16)), |
| (byte) (0xff & (seed >> 8)), |
| (byte) (0xff & seed) |
| }; |
| secureRandomSpi.engineSetSeed(tmp); |
| } |
| } |
| |
| /** |
| Generates a user specified number of bytes. This function |
| is the basis for all the random functions. |
| |
| @param bytes array to store generated bytes in |
| */ |
| public void nextBytes(byte[] bytes) |
| { |
| randomBytesUsed += bytes.length; |
| counter++; |
| secureRandomSpi.engineNextBytes(bytes); |
| } |
| |
| /** |
| Generates an integer containing the user specified |
| number of random bits. It is right justified and padded |
| with zeros. |
| |
| @param numBits number of random bits to get, 0 <= numBits <= 32; |
| |
| @return the random bits |
| */ |
| protected final int next(int numBits) |
| { |
| if (numBits == 0) |
| return 0; |
| |
| byte[] tmp = new byte[numBits / 8 + (1 * (numBits % 8))]; |
| |
| secureRandomSpi.engineNextBytes(tmp); |
| randomBytesUsed += tmp.length; |
| counter++; |
| |
| int ret = 0; |
| |
| for (int i = 0; i < tmp.length; i++) |
| ret |= (tmp[i] & 0xFF) << (8 * i); |
| |
| long mask = (1L << numBits) - 1; |
| return (int) (ret & mask); |
| } |
| |
| /** |
| Returns the given number of seed bytes. This method is |
| maintained only for backwards capability. |
| |
| @param numBytes number of seed bytes to get |
| |
| @return an array containing the seed bytes |
| */ |
| public static byte[] getSeed(int numBytes) |
| { |
| byte[] tmp = new byte[numBytes]; |
| |
| new Random().nextBytes(tmp); |
| return tmp; |
| //return secureRandomSpi.engineGenerateSeed( numBytes ); |
| } |
| |
| /** |
| Returns the specified number of seed bytes. |
| |
| @param numBytes number of seed bytes to get |
| |
| @return an array containing the seed bytes |
| */ |
| public byte[] generateSeed(int numBytes) |
| { |
| return secureRandomSpi.engineGenerateSeed(numBytes); |
| } |
| |
| } |