edu.vt.middleware.crypt.pbe.OpenSSLKeyGenerator.java Source code

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Here is the source code for edu.vt.middleware.crypt.pbe.OpenSSLKeyGenerator.java

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/*
  $Id$
    
  Copyright (C) 2003-2013 Virginia Tech.
  All rights reserved.
    
  SEE LICENSE FOR MORE INFORMATION
    
  Author:  Middleware Services
  Email:   middleware@vt.edu
  Version: $Revision$
  Updated: $Date$
*/
package edu.vt.middleware.crypt.pbe;

import org.bouncycastle.crypto.PBEParametersGenerator;
import org.bouncycastle.crypto.generators.OpenSSLPBEParametersGenerator;
import org.bouncycastle.crypto.params.KeyParameter;

/**
 * Implements a password generation function compatible with the enc operation
 * of OpenSSL in PBE mode. The function is based on a variant of the PBKDF1 key
 * generation function described in PKCS#5v2, but uses an invariant MD5 hash and
 * a fixed iteration count of 1.
 *
 * @author  Middleware Services
 * @version  $Revision$
 */
public class OpenSSLKeyGenerator implements KeyGenerator {

    /** Key generation salt data. */
    private final byte[] salt;

    /**
     * Performs key generation without a salt value. This method is intended for
     * compatibility with old OpenSSL versions or modern OpenSSL versions of the
     * enc command with the -nosalt option.
     */
    public OpenSSLKeyGenerator() {
        this(new byte[0]);
    }

    /**
     * Creates a new key generator with the given salt bytes.
     *
     * @param  saltBytes  Key generation function salt data.
     */
    public OpenSSLKeyGenerator(final byte[] saltBytes) {
        this.salt = saltBytes;
    }

    /** {@inheritDoc} */
    public byte[] generate(final char[] password, final int size) {
        final OpenSSLPBEParametersGenerator generator = new OpenSSLPBEParametersGenerator();
        generator.init(PBEParametersGenerator.PKCS5PasswordToBytes(password), salt);

        final KeyParameter p = (KeyParameter) generator.generateDerivedParameters(size);
        return p.getKey();
    }
}