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.CipherParameters;

public class KeyParameter
    implements CipherParameters
{
    private byte[]  key;

    public KeyParameter(
        byte[]  key)
    {
        this(key, 0, key.length);
    }

    public KeyParameter(
        byte[]  key,
        int     keyOff,
        int     keyLen)
    {
        this.key = new byte[keyLen];

        System.arraycopy(key, keyOff, this.key, 0, keyLen);
    }

    public byte[] getKey()
    {
        return key;
    }
}