How to implement cost-effective and secure public key cryptosystems

Abstract

The smart card has been suggested for personal security in public key cryptosystems. As the size of the keys in public key cryptosystems is increased, the design of crypto-controllers in smart cards becomes more complicated. This paper proposes a secure device in a terminal, "Secure Module", which can support precomputation technique for Schnorr-type cryptosystems such as Schnorr [7], DSA [1], KCDSA [5]. This gives a simple method to implement secure public key cryptosystems without technical efforts to redesign a cryptographic controller in 25mm(2) smart card ICs.