This trivial subclass of Cipher implements an identity cipher that does not transform plain text in any way. Unlike Cipher objects returned by Cipher.getInstance( ), a NullCipher must be created with the NullCipher( ) constructor.

Figure 17-8. javax.crypto.NullCipher

public class NullCipher extends Cipher {
// Public Constructors
     public NullCipher( );  
}