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.asn1;

import java.io.IOException;

public abstract class DERObject
    extends ASN1Encodable
    implements DERTags
{
    public DERObject toASN1Object()
    {
        return this;
    }
    
    public abstract int hashCode();
    
    public abstract boolean equals(Object o);
    
    abstract void encode(DEROutputStream out)
        throws IOException;
}