Byzantine faulty operation recovery and cost analysis of SPURT: A distributed randomness beacon

Abstract

A reliable source of randomness plays an integral part in the design of many cryptographic, security, and distributed system protocols. Yet, existing constructions of distributed random beacons still have limitations such as strong setup or network assumptions, and high computational and communication costs. SPURT a novel efficient distributed randomness beacon protocol does not require any trusted or expensive setup and is secure against a malicious adversary that controls up to one-third of the nodes in a partially synchronous network. One crucial property that SPURT guarantees is unpredictability, which ensures that every honest party is able to recover the random beacon value either before or soon (3 single trip message delays) after the adversary recovers it. This thesis presents the recovery mechanisms that let SPURT provide the above guarantee even in the presence of a malicious leader. We implement SPURT and evaluate it using a network of up to 128 nodes running in geographically distributed AWS instances. Analysis and experiments demonstrated that SPURT offers very high throughput, while only incurring reasonable overhead costs from the recovery mechanisms.