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 to JDK 1.7. 
package org.bouncycastle.jce.interfaces;

import org.bouncycastle.jce.spec.ElGamalParameterSpec;

public interface ElGamalKey
{
    public ElGamalParameterSpec getParameters();
}