On the Chor-Rivest knapsack cryptosystem

Abstract

Among all public-key cryptosystems that depend on the knapsack problem, the system proposed by Chor and Rivest (IEEE Trans. Inform. Theory34 (1988), 901-909) is one of the few that have not been broken. The main difficulty in implementing their system is the computation of discrete logarithms in large finite fields. In this note we describe the "powerline system," which is a modification of the Chor-Rivest system that does not have this shortcoming. The powerline system, which is not a knapsack system, is at least as secure as the original Chor-Rivest system. © 1991 International Association for Cryptologic Research.