Annual International Cryptology Conference

CRYPTO 1995: Advances in Cryptology — CRYPT0’ 95 pp 339-352

Proactive Secret Sharing Or: How to Cope With Perpetual Leakage

  • Amir Herzberg
  • Stanisław Jarecki
  • Hugo Krawczyk
  • Moti Yung
Conference paper

DOI: 10.1007/3-540-44750-4_27

Volume 963 of the book series Lecture Notes in Computer Science (LNCS)

Abstract

Secret sharing schemes protect secrets by distributing them over different locations (share holders). In particular, in k out of n threshold schemes, security is assured if throughout the entire life-time of the secret the adversary is restricted to compromise less than k of the n locations. For long-lived and sensitive secrets this protection may be insufficient.

We propose an efficient proactive secret sharing scheme, where shares are periodically renewed (without changing the secret) in such a way that information gained by the adversary in one time period is useless for attacking the secret after the shares are renewed. Hence, the adversary willing to learn the secret needs to break to all k locations during the same time period (e.g., one day, a week, etc.). Furthermore, in order to guarantee the availability and integrity of the secret, we provide mechanisms to detect maliciously (or accidentally) corrupted shares, as well as mechanisms to secretly recover the correct shares when modification is detected.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1995

Authors and Affiliations

  • Amir Herzberg
    • 1
  • Stanisław Jarecki
    • 1
    • 2
  • Hugo Krawczyk
    • 1
  • Moti Yung
    • 1
  1. 1.IBM T.J. Watson Research CenterYorktown Heights
  2. 2.Laboratory of Computer ScienceMassachusetts Institute of TechnologyUSA