Information Security and Cryptography Research Group

Multi-Valued Byzantine Broadcast: the $t<n$ Case

Martin Hirt and Pavel Raykov

All known protocols implementing broadcast from synchronous point-to-point channels tolerating any $t<n$ Byzantine corruptions have communication complexity at least $\mathrm{\Omega }(\ell n^2)$. We give cryptographically secure and information-theoretically secure protocols for $t<n$ that communicate $O(\ell n)$ bits in order to broadcast sufficiently long $\ell$ bit messages. This matches the optimal communication complexity bound for any protocol allowing to broadcast $\ell$ bit messages. While broadcast protocols with the optimal communication complexity exist in cases where $t<n/3$ (by Liang and Vaidya in PODC '11) or $t<n/2$ (by Fitzi and Hirt in PODC '06), this paper is the first to present such protocols for $t<n$.

BibTeX Citation

@inproceedings{HirRay14,
    author       = {Martin Hirt and Pavel Raykov},
    title        = {Multi-Valued Byzantine Broadcast: the $t < n$ Case},
    booktitle    = {Advances in Cryptology --- ASIACRYPT 2014},
    pages        = {448--465},
    series       = {Lecture Notes in Computer Science},
    volume       = {8874},
    year         = {2014},
    month        = {12},
    publisher    = {Springer},
}

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