@inproceedings{8302, abstract = {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.}, author = {Kokoris Kogias, Eleftherios and Jovanovic, Philipp and Gailly, Nicolas and Khoffi, Ismail and Gasser, Linus and Ford, Bryan}, booktitle = {Proceedings of the 25th USENIX Conference on Security Symposium}, isbn = {9781931971324}, location = {Austin, TX, United States}, pages = {279–296}, publisher = {USENIX Association}, title = {{Enhancing bitcoin security and performance with strong consistency via collective signing}}, year = {2016}, }