International Association for Cryptologic Research

International Association
for Cryptologic Research


Paper: Secure and Efficient Asynchronous Broadcast Protocols

Christian Cachin
Klaus Kursawe
Frank Petzold
Victor Shoup
Search ePrint
Search Google
Abstract: Reliable broadcast protocols are a fundamental building block for implementing replication in fault-tolerant distributed systems. This paper addresses secure service replication in an asynchronous environment with a static set of servers, where a malicious adversary may corrupt up to a threshold of servers and controls the network. We develop a formal model using concepts from modern cryptography, present modular definitions for several broadcast problems, including reliable, atomic, and secure causal broadcast, and present protocols implementing them. Reliable broadcast is a basic primitive, also known as the Byzantine generals problem, providing agreement on a delivered message. Atomic broadcast imposes additionally a total order on all delivered messages. We present a randomized atomic broadcast protocol based on a new, efficient multi-valued asynchronous Byzantine agreement primitive with an external validity condition. Apparently, no such efficient asynchronous atomic broadcast protocol maintaining liveness and safety in the Byzantine model has appeared previously in the literature. Secure causal broadcast extends atomic broadcast by encryption to guarantee a causal order among the delivered messages. Threshold-cryptographic protocols for signatures, encryption, and coin-tossing also play an important role.
  title={Secure and Efficient Asynchronous Broadcast Protocols},
  booktitle={IACR Eprint archive},
  keywords={cryptographic protocols / reliable broadcast, Byzantine agreement, atomic broadcast, distributed cryptography},
  note={ 11388 received 25 Jan 2001, last revised 7 Mar 2001},
  author={Christian Cachin and Klaus Kursawe and Frank Petzold and Victor Shoup},