Paper 2021/1403
Efficient Adaptively-Secure Byzantine Agreement for Long Messages
Amey Bhangale and Chen-Da Liu-Zhang and Julian Loss and Kartik Nayak
Abstract
We investigate the communication complexity of Byzantine agreement protocols for long messages against an adaptive adversary. In this setting, prior results either achieved a communication complexity of $O(nl\cdot\poly(\kappa))$ or $O(nl + n^2 \cdot \poly(\kappa))$ for $l$-bit long messages. We improve the state of the art by presenting protocols with communication complexity $O(nl + n \cdot \poly(\kappa))$ in both the synchronous and asynchronous communication models. The synchronous protocol tolerates $t \le (1-\epsilon) \frac{n}{2}$ corruptions and assumes a VRF setup, while the asynchronous protocol tolerates $t \le (1-\epsilon) \frac{n}{3}$ corruptions under further cryptographic assumptions. Our protocols are very simple and combine subcommittee election with the recent approach of Nayak et al. (DISC `20). Surprisingly, the analysis of our protocols is \emph{all but simple} and involves an interesting new application of Mc Diarmid's inequality to obtain {\em optimal} corruption thresholds.
Metadata
- Available format(s)
- Category
- Cryptographic protocols
- Publication info
- Preprint. MINOR revision.
- Keywords
- Byzantine agreementblockchaincommunication complexity
- Contact author(s)
- cliuzhan @ andrew cmu edu,kartik @ cs duke edu,lossjulian @ gmail com,amey bhangale @ ucr edu
- History
- 2022-06-06: revised
- 2021-10-18: received
- See all versions
- Short URL
- https://ia.cr/2021/1403
- License
-
CC BY