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.jce.interfaces;

import java.security.PrivateKey;
import java.security.PublicKey;


Static/ephemeral private key (pair) for use with ECMQV key agreement
(Optionally provides the ephemeral public key)

/**
 * Static/ephemeral private key (pair) for use with ECMQV key agreement
 * (Optionally provides the ephemeral public key)
 */
public interface MQVPrivateKey
    extends PrivateKey
{
    
return the static private key.

/**
     * return the static private key.
     */
    PrivateKey getStaticPrivateKey();

    
return the ephemeral private key.

/**
     * return the ephemeral private key.
     */
    PrivateKey getEphemeralPrivateKey();

    
return the ephemeral public key (may be null).

/**
     * return the ephemeral public key (may be null).
     */
    PublicKey getEphemeralPublicKey();
}