Extending Asynchronous Byzantine Agreement with Crusader Agreement

Fuente: arXiv
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Main Authors: Erbes, Mose Mizrahi, Wattenhofer, Roger
Format: Preprint
Published: 2025
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author Erbes, Mose Mizrahi
Wattenhofer, Roger
author_facet Erbes, Mose Mizrahi
Wattenhofer, Roger
contents In this work, we study multivalued byzantine agreement (BA) in an asynchronous network of $n$ parties where up to $t < \frac{n}{3}$ parties are byzantine. We present a new reduction from multivalued BA to binary BA. It allows one to achieve BA on $\ell$-bit inputs with one instance of binary BA, one instance of crusader agreement (CA) on $\ell$-bit inputs and $Θ(\ell n + n^2)$ bits of additional communication. As our reduction uses multivalued CA, we also design two new information-theoretic CA protocols for $\ell$-bit inputs. In the first one, we use almost-universal hashing to achieve statistical security with probability $1 - 2^{-λ}$ against $t < \frac{n}{3}$ faults with $Θ(\ell n + n^2(λ+ \log n))$ bits of communication. Following this, we replace the hashes with error correcting code symbols and add a preliminary step based on the synchronous multivalued BA protocol COOL [DISC '21] to obtain a second, perfectly secure CA protocol that can for any $\varepsilon > 0$ be set to tolerate $t \leq \frac{n}{3 + \varepsilon}$ faults with $\mathcal{O}\bigl(\frac{\ell n}{\min(1, \varepsilon^2)} + n^2\max\bigl(1, \log \frac{1}{\varepsilon}\bigr) \bigr)$ bits of communication. Our CA protocols allow one to extend binary BA to multivalued BA with a constant round overhead, a quadratic-in-$n$ communication overhead, and information-theoretic security.
format Preprint
id arxiv_https___arxiv_org_abs_2502_02320
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Extending Asynchronous Byzantine Agreement with Crusader Agreement
Erbes, Mose Mizrahi
Wattenhofer, Roger
Distributed, Parallel, and Cluster Computing
Cryptography and Security
Information Theory
In this work, we study multivalued byzantine agreement (BA) in an asynchronous network of $n$ parties where up to $t < \frac{n}{3}$ parties are byzantine. We present a new reduction from multivalued BA to binary BA. It allows one to achieve BA on $\ell$-bit inputs with one instance of binary BA, one instance of crusader agreement (CA) on $\ell$-bit inputs and $Θ(\ell n + n^2)$ bits of additional communication. As our reduction uses multivalued CA, we also design two new information-theoretic CA protocols for $\ell$-bit inputs. In the first one, we use almost-universal hashing to achieve statistical security with probability $1 - 2^{-λ}$ against $t < \frac{n}{3}$ faults with $Θ(\ell n + n^2(λ+ \log n))$ bits of communication. Following this, we replace the hashes with error correcting code symbols and add a preliminary step based on the synchronous multivalued BA protocol COOL [DISC '21] to obtain a second, perfectly secure CA protocol that can for any $\varepsilon > 0$ be set to tolerate $t \leq \frac{n}{3 + \varepsilon}$ faults with $\mathcal{O}\bigl(\frac{\ell n}{\min(1, \varepsilon^2)} + n^2\max\bigl(1, \log \frac{1}{\varepsilon}\bigr) \bigr)$ bits of communication. Our CA protocols allow one to extend binary BA to multivalued BA with a constant round overhead, a quadratic-in-$n$ communication overhead, and information-theoretic security.
title Extending Asynchronous Byzantine Agreement with Crusader Agreement
topic Distributed, Parallel, and Cluster Computing
Cryptography and Security
Information Theory
url https://arxiv.org/abs/2502.02320