Paper 2002/134

Asynchronous Verifiable Secret Sharing and Proactive Cryptosystems

Christian Cachin, Klaus Kursawe, Anna Lysyanskaya, and Reto Strobl


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.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. Extended abstract appears in ACM CCS-9.
threshold cryptographybyzantine agreement
Contact author(s)
cachin @ acm org
2002-08-29: received
Short URL
Creative Commons Attribution


      author = {Christian Cachin and Klaus Kursawe and Anna Lysyanskaya and Reto Strobl},
      title = {Asynchronous Verifiable Secret Sharing and Proactive Cryptosystems},
      howpublished = {Cryptology ePrint Archive, Paper 2002/134},
      year = {2002},
      note = {\url{}},
      url = {}
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