To achieve these specifications we use the structure of the consensus of Castro-Liskov / [SBFT, Dsn'19], in which we drop-in succinct (range-) proofs of knowledge as a replacement for the forwarding of many messages. We use the same kind of strategy to enable a Fast Track and Strong Unanimity. Namely, we incorporate the additional structure of [SBFT, Dsn'19] and of [Chan et al Podc'19] in the previous protocol. Which we instantiate with proofs of knowledge of: a set of signed messages, from a threshold number of issuers, in which no value appears in majority. The required proofs of knowledge can be obtained from any succinct proof system. Of independent interest, we also introduce alternative elementary proofs, solely based on a black box Threshold Signature Scheme (TSS).
{ Applied } to the state of the art leader-less fully asynchronous consensus protocol [Podc'19], which uses the [Hotstuff, Podc'19] consensus as baseline, this reduces its latency by $25\%$. This speedup directly carries over the state machine replication system [Hotstuff, Podc'19], and thus to Libra. Of independent interest we maintain linear complexity when requiring both External Validity and Halting in finite time, in the Amortized regime over long values. Instantiated with the recent unpublished logarithmic Transparent TSS of Attema et al, none of our protocols requires a trusted setup or a distributed key generation.
Category / Keywords: foundations / Consensus Date: received 25 Nov 2020, last revised 29 Nov 2020 Contact author: matthieu rambaud at telecom-paris fr Available format(s): PDF | BibTeX Citation Version: 20201129:224740 (All versions of this report) Short URL: ia.cr/2020/1480