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Library for performing common cryptographic operations

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/*
  $Id: OpenSSLKeyGenerator.java 1818 2011-02-08 19:19:09Z dfisher $

  Copyright (C) 2007-2011 Virginia Tech.
  All rights reserved.

  SEE LICENSE FOR MORE INFORMATION

  Author:  Middleware Services
  Email:   [email protected]
  Version: $Revision: 1818 $
  Updated: $Date: 2011-02-08 14:19:09 -0500 (Tue, 08 Feb 2011) $
*/
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: 1818 $
 */
public class OpenSSLKeyGenerator implements KeyGenerator
{

  /** Key generation salt data. */
  private 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();
  }
}