Java In A Nutshell, 5th Edition

This interface represents a Diffie-Hellman public key. Note that it extends two interfaces: DHKey and java.security.PublicKey . getY( ) returns the public-key value. If you are working with a PublicKey you know is a Diffie-Hellman key, you can cast your PublicKey to a DHPublicKey .

public interface DHPublicKey extends DHKey, java.security.PublicKey { // Public Constants 5.0 public static final long serialVersionUID ; =-6628103563352519193 // Public Instance Methods java.math.BigInteger getY ( ); }