Limits on the security of coin flips when half the processors are faulty
STOC '86 Proceedings of the eighteenth annual ACM symposium on Theory of computing
Adaptively secure multi-party computation
STOC '96 Proceedings of the twenty-eighth annual ACM symposium on Theory of computing
Reaching Agreement in the Presence of Faults
Journal of the ACM (JACM)
The Byzantine Generals Problem
ACM Transactions on Programming Languages and Systems (TOPLAS)
Universally composable two-party and multi-party secure computation
STOC '02 Proceedings of the thiry-fourth annual ACM symposium on Theory of computing
Unconditional Byzantine Agreement for any Number of Faulty Processors
STACS '92 Proceedings of the 9th Annual Symposium on Theoretical Aspects of Computer Science
Universally Composable Commitments
CRYPTO '01 Proceedings of the 21st Annual International Cryptology Conference on Advances in Cryptology
Non-Interactive and Information-Theoretic Secure Verifiable Secret Sharing
CRYPTO '91 Proceedings of the 11th Annual International Cryptology Conference on Advances in Cryptology
Universally Composable Security: A New Paradigm for Cryptographic Protocols
FOCS '01 Proceedings of the 42nd IEEE symposium on Foundations of Computer Science
Universally Composable Signature, Certification, and Authentication
CSFW '04 Proceedings of the 17th IEEE workshop on Computer Security Foundations
Universally Composable Protocols with Relaxed Set-Up Assumptions
FOCS '04 Proceedings of the 45th Annual IEEE Symposium on Foundations of Computer Science
EUROCRYPT'10 Proceedings of the 29th Annual international conference on Theory and Applications of Cryptographic Techniques
Universally composable synchronous computation
TCC'13 Proceedings of the 10th theory of cryptography conference on Theory of Cryptography
Highly dynamic distributed computing with byzantine failures
Proceedings of the 2013 ACM symposium on Principles of distributed computing
Constant-round adaptive zero-knowledge proofs for NP
Information Sciences: an International Journal
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We consider the classical problem of synchronous broadcast with dishonest majority, when a public-key infrastructure and digital signatures are available. In a surprising result, Hirt and Zikas (Eurocrypt 2010) recently observed that all existing protocols for this task are insecure against an adaptive adversary who can choose which parties to corrupt as the protocol progresses. Moreover, they prove an impossibility result for adaptively secure broadcast in their setting. We argue that the communication model adopted by Hirt and Zikas is unrealistically pessimistic. We revisit the problem of adaptively secure broadcast in a more natural synchronous model (with rushing), and show that broadcast is possible in this setting for an arbitrary number of corruptions. Our positive result holds under a strong, simulation-based definition in the universal-composability framework. We also study the impact of adaptive attacks on protocols for secure multi-party computation where broadcast is used as a sub-routine.