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2018 IEEE Symposium on Security and Privacy (SP) (2018)
San Fransisco, CA, US
May 21, 2018 to May 23, 2018
ISSN: 2375-1207
ISBN: 978-1-5386-4353-2
pp: 19-34
Ewa Syta , Trinity College
Bryan Ford , EPFL
Designing a secure permissionless distributed ledger (blockchain) that performs on par with centralized payment processors, such as Visa, is a challenging task. Most existing distributed ledgers are unable to scale-out, i.e., to grow their total processing capacity with the number of validators; and those that do, compromise security or decentralization. We present OmniLedger, a novel scale-out distributed ledger that preserves long- term security under permissionless operation. It ensures security and correctness by using a bias-resistant public-randomness protocol for choosing large, statistically representative shards that process transactions, and by introducing an efficient cross- shard commit protocol that atomically handles transactions affecting multiple shards. OmniLedger also optimizes performance via parallel intra-shard transaction processing, ledger pruning via collectively-signed state blocks, and low-latency "trust-but- verify" validation for low-value transactions. An evaluation of our experimental prototype shows that OmniLedger's throughput scales linearly in the number of active validators, supporting Visa-level workloads and beyond, while confirming typical transactions in under two seconds.
blockchain, sharding, distributed-ledger, cross-shard, decentralization, Byzantine-Fault-Tolerant, trust-but-verify, scalable, ByzCoinX, Atomix, ledger-pruning, state-blocks, randomness

E. Kokoris-Kogias, P. Jovanovic, L. Gasser, N. Gailly, E. Syta and B. Ford, "OmniLedger: A Secure, Scale-Out, Decentralized Ledger via Sharding," 2018 IEEE Symposium on Security and Privacy (SP), San Fransisco, CA, US, , pp. 19-34.
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