org.jitsi.impl.neomedia.transform.srtp.SHA1.java Source code

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Here is the source code for org.jitsi.impl.neomedia.transform.srtp.SHA1.java

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/*
 * Jitsi, the OpenSource Java VoIP and Instant Messaging client.
 *
 * Distributable under LGPL license.
 * See terms of license at gnu.org.
 */
package org.jitsi.impl.neomedia.transform.srtp;

import org.bouncycastle.crypto.*;
import org.bouncycastle.crypto.digests.*;
import org.jitsi.util.*;

/**
 * Implements a factory for a SHA-1 <tt>Digest</tt>.
 *
 * @author Lyubomir Marinov
 */
public class SHA1 {
    /**
     * The <tt>Logger</tt> used by the <tt>SHA1</tt> class to print out debug
     * information.
     */
    private static final Logger logger = Logger.getLogger(SHA1.class);

    /**
     * The indicator which determines whether the OpenSSL (Crypto) library is to
     * be used. If <tt>true</tt>, an attempt will be made to initialize an
     * <tt>OpenSSLDigest</tt> instance. If the attempt fails, <tt>false</tt>
     * will be assigned in order to not repeatedly attempt the initialization
     * which is known to have failed.
     */
    private static boolean useOpenSSL = true;

    /**
     * Initializes a new <tt>org.bouncycastle.crypto.Digest</tt> instance which
     * implements the SHA-1 cryptographic hash function/digest.
     *
     * @return a new <tt>org.bouncycastle.crypto.Digest</tt> instance which
     * implements the SHA-1 cryptographic hash function/digest
     */
    public static Digest createDigest() {
        // Optionally, use OpenSSL (Crypto).
        if (useOpenSSL) {
            try {
                return new OpenSSLDigest(OpenSSLDigest.SHA1);
            } catch (Throwable t) {
                // If an exception is thrown once, it is very likely to be
                // thrown multiple times.
                useOpenSSL = false;

                if (t instanceof InterruptedException) {
                    Thread.currentThread().interrupt();
                } else if (t instanceof ThreadDeath) {
                    throw (ThreadDeath) t;
                } else {
                    logger.warn("Failed to employ OpenSSL (Crypto) for an optimized" + " SHA-1 implementation: "
                            + t.getLocalizedMessage());
                }
            }
        }

        // Fallback to BouncyCastle.
        return new SHA1Digest();
    }
}