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.asn1;

import java.io.IOException;

public interface ASN1TaggedObjectParser
    extends DEREncodable, InMemoryRepresentable
{
    public int getTagNo();
    
    public DEREncodable getObjectParser(int tag, boolean isExplicit)
        throws IOException;
}