Journal of Cryptology

, Volume 3, Issue 3, pp 149–155 | Cite as

On the Chor—Rivest knapsack cryptosystem

  • H. W. LenstraJr.


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.

Key words

Public-key cryptosystem Finite field 


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    B.-Z. Chor, Two Issues in Public Key Cryptography, RSA Bit Security and a New Knapsack Type System, MIT Press, Cambridge, Mass., 1986.Google Scholar
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Copyright information

© International Association for Cryptologic Research 1991

Authors and Affiliations

  • H. W. LenstraJr.
    • 1
  1. 1.Department of MathematicsUniversity of CaliforniaBerkeleyUSA

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