edu.vt.middleware.crypt.pkcs.PBEParameter.java Source code

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Here is the source code for edu.vt.middleware.crypt.pkcs.PBEParameter.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.pkcs;

import edu.vt.middleware.crypt.util.DERHelper;
import org.bouncycastle.asn1.DERSequence;

/**
 * Describes the PBEParameter type defined in PKCS#5. It can also be used to
 * model the pkcs-12PbeParams type defined in section B.4 of PKCS#12.
 *
 * @author  Middleware Services
 * @version  $Revision$
 */
public class PBEParameter {

    /** Digest salt value. */
    protected byte[] salt;

    /** Number of iterations of mixing function. */
    protected int iterationCount;

    /**
     * Creates a new PBE parameter with given values.
     *
     * @param  saltBytes  Bytes of digest salt.
     * @param  iterations  Number of iterations of mixing function.
     */
    public PBEParameter(final byte[] saltBytes, final int iterations) {
        if (iterations < 1) {
            throw new IllegalArgumentException("Iterations must be greater than 0.");
        }
        this.salt = saltBytes;
        this.iterationCount = iterations;
    }

    /**
     * Decodes a DER sequence of PBE parameters into an instance of this class.
     *
     * @param  params  PBE parameters as a DER sequence.
     *
     * @return  Equivalent instance of {@link PBEParameter}.
     */
    public static PBEParameter decode(final DERSequence params) {
        return new PBEParameter(DERHelper.asOctets(params.getObjectAt(0)), DERHelper.asInt(params.getObjectAt(1)));
    }

    /** @return  the salt */
    public byte[] getSalt() {
        return salt;
    }

    /** @return  the iterationCount */
    public int getIterationCount() {
        return iterationCount;
    }

}