Addition to 'The Existence of Good Cryptosystems for Key Rates Greater Than the Message Redundancy'

Three points related to a previous correspondence are reported here. Two new classes of cryptosystems are shown to share the property of additive-like instantaneous block (ALIB) ciphers; namely, good cryptosystems exist for key rates greater than the message redundancy. Furthermore, the optimality of the independence of the key and the message in a cryptosystem is established.