Paper 2022/164
Shanrang: Fully Asynchronous Proactive Secret Sharing with Dynamic Committees
Yunzhou Yan, Yu Xia, and Srinivas Devadas
Abstract
We present Shanrang, the first fully asynchronous proactive secret sharing scheme with dynamic committee support. Even in the worst possible network environment, where messages could have arbitrary latencies, Shanrang allows a dynamic committee to store a secret and periodically refresh the secret shares in a distributed fashion. When the committee changes, both the old committee and the new committee jointly refresh and transfer the shares to the new committee, without revealing the secret to the adversary. With n parties, Shanrang tolerates n/4 Byzantine faults and maintains liveness as long as the messages are delivered. In contrast to prior work, Shanrang makes no assumptions on the network latency. Designing an asynchronous protocol is challenging because it is impossible to distinguish an adversary sending no messages from an honest party whose messages have not arrived yet. We evaluated Shanrang on geographically distributed machines and we found Shanrang achieved 200 seconds for handing off between 2 committees of 41 parties. Shanrang requires O(λn3 log n) messages and runs in expected O(log n) rounds for every handoff. To show Shanrang is robust even in a harsh network environ- ment, we test Shanrang on the Tor network and it shows robust performance.
Metadata
- Available format(s)
-
PDF
- Category
- Cryptographic protocols
- Publication info
- Preprint. MINOR revision.
- Keywords
- secret sharingthreshold cryptography
- Contact author(s)
-
yanyz18 @ mails tsinghua edu cn
yuxia @ mit edu
devadas @ mit edu - History
- 2022-02-20: received
- Short URL
- https://ia.cr/2022/164
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2022/164,
author = {Yunzhou Yan and Yu Xia and Srinivas Devadas},
title = {Shanrang: Fully Asynchronous Proactive Secret Sharing with Dynamic Committees},
howpublished = {Cryptology {ePrint} Archive, Paper 2022/164},
year = {2022},
url = {https://eprint.iacr.org/2022/164}
}