Fault tolerance in networks of bounded degree
SIAM Journal on Computing
Tolerating a linear number of faults in networks of bounded degree
Information and Computation
Lower bounds for distributed coin-flipping and randomized consensus
STOC '97 Proceedings of the twenty-ninth annual ACM symposium on Theory of computing
A tight lower bound for randomized synchronous consensus
PODC '98 Proceedings of the seventeenth annual ACM symposium on Principles of distributed computing
Distributed Algorithms
Censorship resistant peer-to-peer content addressable networks
SODA '02 Proceedings of the thirteenth annual ACM-SIAM symposium on Discrete algorithms
Building Low-Diameter P2P Networks
FOCS '01 Proceedings of the 42nd IEEE symposium on Foundations of Computer Science
Distributed Computing: Fundamentals, Simulations and Advanced Topics
Distributed Computing: Fundamentals, Simulations and Advanced Topics
How to spread adversarial nodes?: rotate!
Proceedings of the thirty-seventh annual ACM symposium on Theory of computing
Information dissemination in highly dynamic graphs
DIALM-POMC '05 Proceedings of the 2005 joint workshop on Foundations of mobile computing
Fast consensus in networks of bounded degree
Distributed Computing
SODA '06 Proceedings of the seventeenth annual ACM-SIAM symposium on Discrete algorithm
Towards Secure and Scalable Computation in Peer-to-Peer Networks
FOCS '06 Proceedings of the 47th Annual IEEE Symposium on Foundations of Computer Science
The Effect of Faults on Network Expansion
Theory of Computing Systems
How to Explore a Fast-Changing World (Cover Time of a Simple Random Walk on Evolving Graphs)
ICALP '08 Proceedings of the 35th international colloquium on Automata, Languages and Programming, Part I
Towards a Scalable and Robust DHT
Theory of Computing Systems - Special Issue: Symposium on Parallelism in Algorithms and Architectures 2006; Guest Editors: Robert Kleinberg and Christian Scheideler
A Distributed and Oblivious Heap
ICALP '09 Proceedings of the 36th Internatilonal Collogquium on Automata, Languages and Programming: Part II
Distributed computation in dynamic networks
Proceedings of the forty-second ACM symposium on Theory of computing
Fast asynchronous Byzantine agreement and leader election with full information
ACM Transactions on Algorithms (TALG)
Breaking the O(n2) bit barrier: scalable byzantine agreement with an adaptive adversary
Proceedings of the 29th ACM SIGACT-SIGOPS symposium on Principles of distributed computing
Stabilizing consensus with the power of two choices
Proceedings of the twenty-third annual ACM symposium on Parallelism in algorithms and architectures
Coordinated consensus in dynamic networks
Proceedings of the 30th annual ACM SIGACT-SIGOPS symposium on Principles of distributed computing
Time-varying graphs and dynamic networks
ADHOC-NOW'11 Proceedings of the 10th international conference on Ad-hoc, mobile, and wireless networks
Towards robust and efficient computation in dynamic peer-to-peer networks
Proceedings of the twenty-third annual ACM-SIAM symposium on Discrete Algorithms
Fast distributed computation in dynamic networks via random walks
DISC'12 Proceedings of the 26th international conference on Distributed Computing
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We study Byzantine agreement in dynamic networks where topology can change from round to round and nodes can also experience heavy churn (i.e., nodes can join and leave the network continuously over time). Our main contributions are randomized distributed algorithms that achieve almost-everywhere Byzantine agreement with high probability even under a large number of adaptively chosen Byzantine nodes and continuous adversarial churn in a number of rounds that is polylogarithmic in n (where n is the stable network size). We show that our algorithms are essentially optimal (up to polylogarithmic factors) with respect to the amount of Byzantine nodes and churn rate that they can tolerate by showing a lower bound. In particular, we present the following results: 1. An O(log3 n) round randomized algorithmto achieve almost everywhere Byzantine agreement with high probability under a presence of up to O(√n/polylog(n)) Byzantine nodes and up to a churn of O(√n/polylog(n)) nodes per round. We assume that the Byzantine nodes have knowledge about the entire state of network at every round (including random choices made by all the nodes) and can behave arbitrarily. We also assume that an adversary controls the churn - it has complete knowledge and control of what nodes join and leave and at what time and has unlimited computational power (but is oblivious to the topology changes from round to round). Our algorithm requires only polylogarithmic in n bits to be processed and sent (per round) by each node. 2. We also present an O(log3 n) round randomized algorithm that has same guarantees as the above algorithm, but works even when the connectivity of the network is controlled by an adaptive adversary (that can choose the topology based on the current states of the nodes). However, this algorithm requires up to polynomial in n bits to be processed and sent (per round) by each node. 3. We show that the above bounds are essentially the best possible, if one wants fast (i.e., polylogarithmic run time) algorithms, by showing that any (randomized) algorithm to achieve agreement in a dynamic network controlled by an adversary that can churn up to Θ(√n log n) nodes per round should take at least a polynomial number of rounds. Our algorithms are the first-known, fully distributed, Byzantine agreement algorithms in highly dynamic networks. We view our results as a step towards understanding the possibilities and limitations of highly dynamic networks that are subject to malicious behavior by a large number of nodes.