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.util;

public interface Selector
    extends Cloneable
{
    boolean match(Object obj);

    Object clone();
}