/*
* Copyright (C)2009 - SSHJ Contributors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package net.schmizz.sshj.transport.random;
import java.security.SecureRandom;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/** A {@link Random} implementation using the built-in {@link SecureRandom} PRNG. */
public class JCERandom
implements Random {
private static final Logger logger = LoggerFactory.getLogger(JCERandom.class);
/** Named factory for the JCE {@link Random} */
public static class Factory
implements net.schmizz.sshj.common.Factory.Named<Random> {
@Override
public Random create() {
return new JCERandom();
}
@Override
public String getName() {
return "default";
}
}
private byte[] tmp = new byte[16];
private final SecureRandom random;
JCERandom() {
logger.info("Creating new SecureRandom.");
long t = System.currentTimeMillis();
random = new SecureRandom();
logger.debug("Random creation took {} ms", System.currentTimeMillis() - t);
}
/**
* Fill the given byte-array with random bytes from this PRNG.
*
* @param foo the byte-array
* @param start the offset to start at
* @param len the number of bytes to fill
*/
@Override
public synchronized void fill(byte[] foo, int start, int len) {
if (start == 0 && len == foo.length) {
random.nextBytes(foo);
} else {
synchronized (this) {
if (len > tmp.length)
tmp = new byte[len];
random.nextBytes(tmp);
System.arraycopy(tmp, 0, foo, start, len);
}
}
}
@Override
public void fill(final byte[] bytes) {
random.nextBytes(bytes);
}
}