International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Asynchronous Verifiable Secret Sharing and Proactive Cryptosystems

Christian Cachin
Klaus Kursawe
Anna Lysyanskaya
Reto Strobl
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Abstract: Verifiable secret sharing is an important primitive in distributed cryptography. With the growing interest in the deployment of threshold cryptosystems in practice, the traditional assumption of a synchronous network has to be reconsidered and generalized to an asynchronous model. This paper proposes the first \emph{practical} verifiable secret sharing protocol for asynchronous networks. The protocol creates a discrete logarithm-based sharing and uses only a quadratic number of messages in the number of participating servers. It yields the first asynchronous Byzantine agreement protocol in the standard model whose efficiency makes it suitable for use in practice. Proactive cryptosystems are another important application of verifiable secret sharing. The second part of this paper introduces proactive cryptosystems in asynchronous networks and presents an efficient protocol for refreshing the shares of a secret key for discrete logarithm-based sharings.
  title={Asynchronous Verifiable Secret Sharing and Proactive Cryptosystems},
  booktitle={IACR Eprint archive},
  keywords={cryptographic protocols / threshold cryptography, byzantine agreement},
  note={Extended abstract appears in ACM CCS-9. 11928 received 29 Aug 2002},
  author={Christian Cachin and Klaus Kursawe and Anna Lysyanskaya and Reto Strobl},