http://www.bouncycastle.org/java.html: The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5. 
package org.bouncycastle.crypto.params;

import org.bouncycastle.crypto.DerivationParameters;


parameters for mask derivation functions.

/**
 * parameters for mask derivation functions.
 */
public class MGFParameters
    implements DerivationParameters
{
    byte[]  seed;

    public MGFParameters(
        byte[]  seed)
    {
        this(seed, 0, seed.length);
    }

    public MGFParameters(
        byte[]  seed,
        int     off,
        int     len)
    {
        this.seed = new byte[len];
        System.arraycopy(seed, off, this.seed, 0, len);
    }

    public byte[] getSeed()
    {
        return seed;
    }
}