OmniLedger: A Secure, Scale-Out, Decentralized Ledger via Sharding
Eleftherios Kokoris-Kogias,
Philipp Jovanovic,
Linus Gasser,
Nicolas Gailly,
Ewa Syta, and
Bryan Ford
IEEE Security & Privacy (IEEE S&P)
May 22, 2018
Abstract:
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 longterm
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 crossshard
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-butverify”
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.
Paper:
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