We introduce CHURP (CHUrn-Robust Proactive secret sharing). CHURP enables secure secret sharing in dynamic settings, where the committee of nodes storing a secret changes over time. Designed for blockchains, CHURP has lower communication complexity than previous schemes: O(n) on-chain and O(n^2) off-chain in the optimistic case of no node failures.
CHURP includes several technical innovations: An efficient new proactivization scheme, a technique (using asymmetric bivariate polynomials) for efficiently changing secret-sharing thresholds, and a hedge against setup failures in an efficient polynomial commitment scheme. We report on the functionality and implementation of CHURP, and present performance improvements.
Title
Proactive Secret Sharing in Dynamic Environments
Published
2019-05-17
Full Collection Name
Electrical Engineering & Computer Sciences Technical Reports
Other Identifiers
EECS-2019-62
Type
Text
Extent
41 p
Archive
The Engineering Library
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