com.adaptris.security.util.SecurityUtil.java Source code

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Here is the source code for com.adaptris.security.util.SecurityUtil.java

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/*
 * Copyright 2015 Adaptris Ltd.
 * 
 * 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 com.adaptris.security.util;

import java.security.Provider;
import java.security.SecureRandom;
import java.security.Security;
import java.util.Arrays;

import org.apache.commons.logging.Log;
import org.bouncycastle.crypto.digests.SHA384Digest;
import org.bouncycastle.crypto.prng.DigestRandomGenerator;
import org.bouncycastle.crypto.prng.SP800SecureRandomBuilder;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

/**
 * Security Utilities.
 *
 * @see SecureRandom
 * @author $Author: lchan $
 */
public final class SecurityUtil {

    private static boolean initialised = false;

    private static SecureRandom secureRandomInstance;

    /** Default constructor */
    private SecurityUtil() {
    }

    /**
     * Add a JCE provider.
     * <p>
     * This also performs the SeedGenerator initialisation, and is only performed
     * once, regardless of how many times this method is invoked
     * </p>
     */
    public static void addProvider() {
        initialise();
    }

    /**
     * Return a SecureRandom implementation.
     * 
     * @return a SecureRandom instance.
     */
    public static SecureRandom getSecureRandom() {
        initialise();
        return secureRandomInstance;
    }

    /**
     * Print out all the algorithms provided by each provider to the specified
     * logger.
     *
     * @param logR the Log to be used for this output.
     */
    public static void printAlgorithms(Log logR) {
        if (logR.isDebugEnabled() && Constants.DEBUG) {
            logR.debug(getAlgorithms());
        }
    }

    public static String getAlgorithms() {
        initialise();
        StringBuffer sb = new StringBuffer("Security Algorithms available");
        for (Provider provider : Security.getProviders()) {
            sb.append("\nProvider : " + provider.toString() + "\n");

            Object[] objs = provider.keySet().toArray();
            Arrays.sort(objs);
            for (Object o : objs) {
                sb.append(o.toString() + ", ");
            }
        }
        return sb.toString();
    }

    private static synchronized void initialise() {
        if (initialised) {
            return;
        }

        Security.addProvider(new BouncyCastleProvider());

        initSecureRandom();
        initialised = true;
        return;
    }

    private static void initSecureRandom() {
        SP800SecureRandomBuilder rngb = new SP800SecureRandomBuilder();
        SHA384Digest sha384 = new SHA384Digest();
        byte[] bytes = new byte[sha384.getDigestSize()];
        new DigestRandomGenerator(sha384).nextBytes(bytes);
        secureRandomInstance = rngb.buildHash(sha384, bytes, true);
    }
}