Enhancing Bitcoin Security and Performance with Strong Consistency via Collective Signing

• Presented at: 25th USENIX Security Symposium, Austin, TX, AUG 10-12, 2016
• Published in: Proceedings Of The 25Th Usenix Security Symposium (ISBN: 978-1-931971-32-4), p. 279-296
• Berkeley: Usenix Assoc, 2016

While showing great promise, Bitcoin requires users to wait tens of minutes for transactions to commit, and even then, offering only probabilistic guarantees. This paper introduces ByzCoin, a novel Byzantine consensus protocol that leverages scalable collective signing to commit Bitcoin transactions irreversibly within seconds. ByzCoin achieves Byzantine consensus while preserving Bitcoin's open membership by dynamically forming hash power-proportionate consensus groups that represent recently-successful block miners. ByzCoin employs communication trees to optimize transaction commitment and verification under normal operation while guaranteeing safety and liveness under Byzantine faults, up to a near-optimal tolerance of f faulty group members among 3f + 2 total. ByzCoin mitigates double spending and selfish mining attacks by producing collectively signed transaction blocks within one minute of transaction submission. Tree-structured communication further reduces this latency to less than 30 seconds. Due to these optimizations, ByzCoin achieves a throughput higher than PayPal currently handles, with a confirmation latency of 15-20 seconds.

Reference

• EPFL-CONF-220209
• View record in Web of Science

Record created on 2016-07-28, modified on 2017-03-20