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The Bouncy Castle Java APIs for CMS, PKCS, EAC, TSP, CMP, CRMF, OCSP, and certificate generation. The APIs are designed primarily to be used in conjunction with the BC FIPS provider. The APIs may also be used with other providers although if being used in a FIPS context it is the responsibility of the user to ensure that any other providers used are FIPS certified.

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package org.bouncycastle.operator;

import org.bouncycastle.asn1.ASN1ObjectIdentifier;
import org.bouncycastle.asn1.misc.MiscObjectIdentifiers;

/**
 * Configuration class for a PBKDF based around scrypt.
 */
public class ScryptConfig
    extends PBKDFConfig
{
    public static class Builder
    {
        private final int costParameter;
        private final int blockSize;
        private final int parallelizationParameter;

        private int saltLength = 16;

        /**
         * Base constructor.
         *
         * @param costParameter cost parameter (must be a power of 2)
         * @param blockSize block size
         * @param parallelizationParameter parallelization parameter
         */
        public Builder(int costParameter, int blockSize, int parallelizationParameter)
        {
            if (costParameter <= 1 || !isPowerOf2(costParameter))
            {
                throw new IllegalArgumentException("Cost parameter N must be > 1 and a power of 2");
            }

            this.costParameter = costParameter;
            this.blockSize = blockSize;
            this.parallelizationParameter = parallelizationParameter;
        }

        /**
         * Set the length of the salt to use.
         *
         * @param saltLength the length of the salt (in octets) to use.
         * @return the current builder.
         */
        public Builder withSaltLength(int saltLength)
        {
            this.saltLength = saltLength;

            return this;
        }

        public ScryptConfig build()
        {
            return new ScryptConfig(this);
        }

        // note: we know X is non-zero
        private static boolean isPowerOf2(int x)
        {
            return ((x & (x - 1)) == 0);
        }
    }

    private final int costParameter;
    private final int blockSize;
    private final int parallelizationParameter;
    private final int saltLength;

    private ScryptConfig(Builder builder)
    {
        super(new ASN1ObjectIdentifier("1.3.6.1.4.1.11591.4.11"));

        this.costParameter = builder.costParameter;
        this.blockSize = builder.blockSize;
        this.parallelizationParameter = builder.parallelizationParameter;
        this.saltLength = builder.saltLength;
    }

    public int getCostParameter()
    {
        return costParameter;
    }

    public int getBlockSize()
    {
        return blockSize;
    }

    public int getParallelizationParameter()
    {
        return parallelizationParameter;
    }

    public int getSaltLength()
    {
        return saltLength;
    }
}