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.

Figure 17-13. javax.crypto.interfaces.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( );  
}