Always Have a Backup Plan: Fully Secure Synchronous MPC with Asynchronous Fallback

Blum, Erica; Liu-Zhang, Chen-Da; Loss, Julian

doi:10.1007/978-3-030-56880-1_25

Cited by 23 publications

(31 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Protocols achieving security guarantees in both synchronous and asynchronous networks have only begun to be studied in relatively recent works. Closest to ours are works by Blum et al [9,11], which consider the problem of BA and MPC achieving security guarantees in both communication models. Our work improves upon the round efficiency of these protocols.…”

Section: Related Workmentioning

confidence: 94%

“…A recent line of work [9,11] provides BA and MPC protocols that are secure up to t s < n/2 corruptions when the network is synchronous, and t a ≤ t s corruptions when the network is asynchronous, for the optimal trade-off t a + 2t s < n.…”

Section: Contributionsmentioning

confidence: 99%

Section: Contributionsmentioning

confidence: 99%

“…Current BA and MPC protocols in this realm [9,11] require a linear number of rounds in the number of parties. Moreover, known MPC protocols [11] also have linear round complexity in the depth of the circuit to evaluate. This is in contrast to the efficiency of state-of-the-art purely synchronous protocols: fixedround BA protocols (Monte-Carlo type) require only O(κ) rounds, and BA protocols with probabilistic termination (Las-Vegas type) require an expected constant number of rounds.…”

Section: Contributionsmentioning

confidence: 99%

“…We obtain the first synchronous MPC protocol with asynchronous fallback with optimal guarantees (i.e. t a +2t s < n and (n−t s )-output quality as in [11]) that requires a constant number of all-to-all broadcast/BA invocations. In particular, the round complexity is independent of the depth of the circuit.…”

Section: Contributionsmentioning

confidence: 99%

See 4 more Smart Citations

Round-Efficient Byzantine Agreement and Multi-party Computation with Asynchronous Fallback

Deligios

Hirt

Liu-Zhang

2021

Lecture Notes in Computer Science

Self Cite

View full text Add to dashboard Cite

Protocols for Byzantine agreement (BA) and secure multi-party computation (MPC) can be classified according to the underlying communication model. The two most commonly considered models are the synchronous one and the asynchronous one. Synchronous protocols typically lose their security guarantees as soon as the network violates the synchrony assumptions. Asynchronous protocols remain secure regardless of the network conditions, but achieve weaker security guarantees even when the network is synchronous. Recent works by Blum, Katz and Loss [TCC'19], and Blum, Liu-Zhang and Loss [CRYPTO'20] introduced BA and MPC protocols achieving security guarantees in both settings: security up to ts corruptions in a synchronous network, and up to ta corruptions in an asynchronous network, under the provably optimal threshold trade-offs ta ≤ ts and ta + 2ts < n. However, current solutions incur a high synchronous round complexity when compared to state-of-the-art purely synchronous protocols. When the network is synchronous, the round complexity of BA protocols is linear in the number of parties, and the round complexity of MPC protocols also depends linearly on the depth of the circuit to evaluate. In this work, we provide round-efficient constructions for both primitives with optimal resilience: fixed-round and expected constant-round BA protocols, and an MPC protocol whose round complexity is independent of the circuit depth.

show abstract

Section: Related Workmentioning

confidence: 94%

Section: Contributionsmentioning

confidence: 99%