org.apache.sshd.common.random.JceRandom Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of wildfly-client-all

This artifact provides a single jar that contains all classes required to use remote Jakarta Enterprise Beans and Jakarta Messaging, including all dependencies. It is intended for use by those not using maven, maven users should just import the Jakarta Enterprise Beans and Jakarta Messaging BOM's instead (shaded JAR's cause lots of problems with maven, as it is very easy to inadvertently end up with different versions on classes on the class path).

The newest version!

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you 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 org.apache.sshd.common.random;

import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A Random implementation using the built-in {@link SecureRandom} PRNG.
 *
 * @author Apache MINA SSHD Project
 */
public class JceRandom extends AbstractRandom {

    public static final String NAME = "JCE";

    private static final Logger LOG = LoggerFactory.getLogger(JceRandom.class);

    private byte[] tmp = new byte[16];
    private final SecureRandom random = getRandom();

    public JceRandom() {
        super();
    }

    private static SecureRandom getRandom() {
        try {
            return SecureRandom.getInstanceStrong();
        } catch (NoSuchAlgorithmException e) {
            LOG.warn("No strong SecureRandom algorithm available; falling back to non-strong SecureRandom PRNG.");
            return new SecureRandom();
        }
    }

    private static final class Cache {

        static final SecureRandom INSTANCE = getRandom();

        private Cache() {
            // No instantiation
            super();
        }
    }

    public static SecureRandom getGlobalInstance() {
        return Cache.INSTANCE;
    }

    @Override
    public String getName() {
        return NAME;
    }

    @Override
    public synchronized void fill(byte[] foo, int start, int len) {
        if ((start == 0) && (len == foo.length)) {
            random.nextBytes(foo);
        } else {
            if (len > tmp.length) {
                tmp = new byte[len];
            }
            random.nextBytes(tmp);
            System.arraycopy(tmp, 0, foo, start, len);
        }
    }

    @Override
    public synchronized int random(int n) {
        return random.nextInt(n);
    }
}