Asynchronous Proactive Cryptosystems Without Agreement (Extended Abstract)

d abstract) Bartosz Przydatek1 and Reto Strobl2 1 Department of Computer Science, ETH Z¨urich, Switzerland 2 IBM Research, Zurich Research Laboratory, Switzerland In this paper, we present efficient asynchronous protocols that allow to build proactive cryptosystems secure against a mobile fail-stop adversary. Such systems distribute the power of a public-key cryptosystem among a set of servers, so that the security and functionality of the overall system is preserved against an adversary that crashes and/or eavesdrops every server repeatedly and transiently, but no more than a certain fraction of the servers at a given time. The building blocks of proactive cryptosystems — to which we present novel solutions — are protocols for joint random secret sharing and for proactive secret sharing. The first protocol provides every server with a share of a random value unpredictable by the adversary, and the second allows to change the shared representation of a secret value. Synchronous ...

• Type: Conference
• Year: 2004
• Where: ASIACRYPT
• Authors: Bartosz Przydatek, Reto Strobl
• Keywords: ASIACRYPT 2004, Cryptology, Efficient Asynchronous Protocols, Mobile Fail-stop Adversary, Proactive Cryptosystems