/*
* Copyright 2005 Sun Microsystems, Inc. All Rights Reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Sun designates this
* particular file as subject to the "Classpath" exception as provided
* by Sun in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
* CA 95054 USA or visit www.sun.com if you need additional information or
* have any questions.
*/
package sun.security.mscapi;
import java.security.ProviderException;
import java.security.SecureRandomSpi;
/**
* Native PRNG implementation for Windows using the Microsoft Crypto API.
*
* @since 1.6
*/
public final class PRNG extends SecureRandomSpi
implements java.io.Serializable {
// TODO - generate the serialVersionUID
//private static final long serialVersionUID = XXX;
/*
* The CryptGenRandom function fills a buffer with cryptographically random
* bytes.
*/
private static native byte[] generateSeed(int length, byte[] seed);
/**
* Creates a random number generator.
*/
public PRNG() {
}
/**
* Reseeds this random object. The given seed supplements, rather than
* replaces, the existing seed. Thus, repeated calls are guaranteed
* never to reduce randomness.
*
* @param seed the seed.
*/
protected void engineSetSeed(byte[] seed) {
if (seed != null) {
generateSeed(-1, seed);
}
}
/**
* Generates a user-specified number of random bytes.
*
* @param bytes the array to be filled in with random bytes.
*/
protected void engineNextBytes(byte[] bytes) {
if (bytes != null) {
if (generateSeed(0, bytes) == null) {
throw new ProviderException("Error generating random bytes");
}
}
}
/**
* Returns the given number of seed bytes. This call may be used to
* seed other random number generators.
*
* @param numBytes the number of seed bytes to generate.
*
* @return the seed bytes.
*/
protected byte[] engineGenerateSeed(int numBytes) {
byte[] seed = generateSeed(numBytes, null);
if (seed == null) {
throw new ProviderException("Error generating seed bytes");
}
return seed;
}
}
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