Proactive Secret Sharing Schemes with Different Security Levels
Conference Proceeding Article
Secret sharing schemes protect a secret by distributing the shares of the secret over different locations (share-holders). Recently, Proactive Secret Sharing (PSS) was introduced  to protect long-lived secrets in the presence of corrupted share-holders. In a PSS scheme, the life-time of a secret is divided into multiple periods, and the shares are periodically renewed so that the secret is protected even if every share-holder may be corrupted in some periods but no more than t share-holders are corrupted in each single period. In this paper, we consider PSS schemes in a different model from the one used in . This model makes it possible to study the different levels of the security of PSS. We first show that there is an information-theoretically secure (i.e., both unconditional secrecy and unconditional resilience) PSS scheme with exponential complexity. We then present two PSS schemes with polynomial complexity - the first one has unconditional resilience but conditional secrecy; while the second one has unconditional secrecy but conditional resilience. We conjecture that there does not exist any information-theoretically secure PSS schemes with polynomial complexity.
cryptography, distributed computing, secret sharing
Proceedings of ChinaCrypt 2000
City or Country
BAO, Feng and DENG, Robert H..
Proactive Secret Sharing Schemes with Different Security Levels. (2000). Proceedings of ChinaCrypt 2000. 92-101. Research Collection School Of Information Systems.
Available at: http://ink.library.smu.edu.sg/sis_research/1112