Handel: Practical Multi-Signature Aggregation for Large Byzantine Committees
This work addresses the scalability and performance challenges for distributed systems like blockchains that rely on multi-signature schemes, representing a significant but incremental improvement in Byzantine-tolerant protocols.
The paper tackles the problem of efficiently aggregating cryptographic signatures across large, geographically distributed committees in the presence of Byzantine faults, achieving aggregation of 4000 signatures in under 900 milliseconds with an average per-node communication cost of 56KB.
We present Handel, a Byzantine-tolerant aggregation protocol that allows for the quick aggregation of cryptographic signatures over a WAN. Handel has polylogarithmic time, communication and processing complexity. We implemented Handel as an open source Go library with a flexible design to support any associative and commutative aggregation function. We tested Handel on 2000 AWS instances running two nodes per instance and located in 10 AWS regions. The 4000 signatures are aggregated in less than 900 milliseconds with an average per-node communication cost of 56KB.