Self-stabilizing byzantine agreement

Self Cite

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

“…The consensus-broadcast and the broadcast primitives are dened in [9]. Note that an accept is issued within the broadcast primitive.…”

Section: Discussionmentioning

confidence: 99%

Section: Endmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Self-stabilization of Byzantine Protocols

Daliot

Dolev

2005

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Self-stabilizing Byzantine Clock Synchronization with Optimal Precision

Khanchandani

Lenzen

2016

In the Byzantine-tolerant clock synchronization problem, the goal is to synchronize the clocks of n fully connected nodes. The clocks run at rates between 1 and ϑ > 1, and messages have a delay (including computation) between d − U and d. Moreover, up to f < n/3 of the nodes can fail by deviating arbitrarily from the protocol, i.e., are Byzantine. Despite this interference, correct nodes need to generate distinguished events (or pulses) almost simultaneously and periodically. The quality of the solution is measured by the skew, which is the maximum real time difference between corresponding pulses. In the self-stabilizing setting, in addition we allow for transient failures, possibly of all nodes. Once transient faults have ceased and at most f nodes remain faulty, the system should start generating synchronized pulses again. We design a self-stabilizing solution to this problem with asymptotically optimal skew. We achieve our goal by refining and extending the protocol of Lynch and Welch and make the following contributions in the process.-We give a simple analysis of the Lynch and Welch protocol with improved bounds on skew and tolerable difference in clock rates by rebuilding upon the main ingredient of their protocol, called approximate agreement. -We give a modified version of the protocol so that the frequency and amount of communication between the nodes is reduced. The modification adds a step to adjust the clock rates by another application of approximate agreement. The skew bound achieved is asymptotically optimal for suitable choices of parameters. -We present a method to add self-stabilization to the above protocols while preserving their skew bounds. The heart of the method is a coupling scheme that leverages a self-stabilizing protocol with a larger skew.

Near-Optimal Self-stabilising Counting and Firing Squads

Lenzen

Rybicki

2016

Consider a fully-connected synchronous distributed system consisting of n nodes, where up to f nodes may be faulty and every node starts in an arbitrary initial state. In the synchronous C-counting problem, all nodes need to eventually agree on a counter that is increased by one modulo C in each round for given C > 1. In the self-stabilising firing squad problem, the task is to eventually guarantee that all non-faulty nodes have simultaneous responses to external inputs: if a subset of the correct nodes receive an external "go" signal as input, then all correct nodes should agree on a round (in the not-too-distant future) in which to jointly output a "fire" signal. Moreover, no node should generate a "fire" signal without some correct node having previously received a "go" signal as input. We present a framework reducing both tasks to binary consensus at very small cost. For example, we obtain a deterministic algorithm for self-stabilising Byzantine firing squads with optimal resilience f < n/3, asymptotically optimal stabilisation and response time O( f ), and message size O(log f ). As our framework does not restrict the type of consensus routines used, we also obtain efficient randomised solutions.