Communicating Reliably in Multihop Dynamic Networks Despite Byzantine Failures

Abstract

We consider the following problem: two nodes want to reliably communicate in a dynamic multihop network where some nodes have been compromised, and may have a totally arbitrary and unpredictable behavior. These nodes are called Byzantine. We consider the two cases where cryptography is available and not available.We prove the necessary and sufficient condition (that is, the weakest possible condition) to ensure reliable communication in this context. Our proof is constructive, as we provide Byzantineresilient algorithms for reliable communication that are optimal with respect to our impossibility results.In a second part, we investigate the impact of our conditions in three case studies: participants interacting in a conference, robots moving on a grid and agents in the subway. Our simulations indicate a clear benefit of using our algorithms for reliable communication in those contexts.

Reliable Broadcast in Dynamic Networks with Locally Bounded Byzantine Failures

“…The analysis of this simple algorithm is important as it works exploiting only local knowledge. This contrasts to the best result so far in the same setting [15], that demands an exponential costs to check when a message can be delivered. Moreover, we presented necessary and sufficient conditions to ensure safety and liveness DCPA.…”

“…Adapting to dynamic networks proved difficult, as the topology assumptions made by the mentioned proposals may no longer hold: the network changes during the execution. Some core problems of distributed computing have been considered in the context of dynamic networks subject to Byzantine failures [1,8] but, to the best of our knowledge, there exists a single contribution for the reliable communication problem, due to Maurer et al [15]. Their work can be seen as the dynamic network extension of the Dolev [5] solution for static networks, and assumes that no more than f Byzantine processes are present in the network.…”

“…In this paper, we investigate the possibility of reliable broadcast in a dynamic network that is subject to Byzantine faults. More precisely, we address the possibility of a local criterion on the number of Byzantine (as opposed to a global criterion as in Maurer et al [15]) in the hope that a practically efficient protocol can be derived in case the criterion is satisfied. Our starting point is the CPA protocol [2,10,16,18], that was originally designed for static networks.…”

Practical Byzantine Reliable Broadcast on Partially Connected Networks

“…Indeed, a few modifications allow to save messages, making the algorithm more appealing from a practical point of view even if its worst-case complexity still remains high. Maurer et al [10] considered the reliable communication problem in settings where the topology can vary with time. In Maurer et al's protocol, a process needs to solve the minimum vertex cut problem instead of the not equivalent (in dynamic networks) maximum disjoint paths problem.…”

Multi-hop Byzantine reliable broadcast with honest dealer made practical

“…There exists two solutions addressing the Byzantine Reliable Broadcast with honest dealer problem in the system model we considered, that are the Dolev [7] and the Maurer et al [20] algorithms. Any other solutions for the BRB problem makes extra or different assumptions (e.g.…”