A Realization Scheme for the Identity-Based Cryptosystem

  • Hatsukazu Tanaka
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 293)


At the Crypto’84, Shamir has presented a new concept of the identity-based cryptosystem, but no idea is presented on the realization scheme. In this paper a new realization scheme of the modified identity-based cryptosystem has been proposed. The basic idea of the scheme is based on the discrete logarithm problem and the difficulty of factoring a large integer composed of two large primes. The scheme seems to be very secure if all members of the system keep their secret keys safe, but if a constant number of users conspire, the center secret will be disclosed, Then it has a close relation to the well-known “threshold scheme”. To cope with the conspiracy, the basic system is extended to get a new scheme of which “threshold” becomes higher. Detail considerations on the scheme are also given.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1988

Authors and Affiliations

  • Hatsukazu Tanaka
    • 1
  1. 1.Department of Electrical EngineeringKobe UniversityRokko, Nada, KobeJapan

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