In this paper we assume the same key pre-distribution set-up but consider a semi-honest adversary. Semi-honest adversaries are privacy adversaries that have access to a fraction of the keys in the key pool, the compromised keys, but are otherwise passive, in the sense that they do not cause nodes to deviate from protocol executions (to remain undetectable). Since they can decrypt messages secured by key-paths with compromised keys, the security guarantees of the EG model break down.
We revisit the security of key establishment in the presence of such adversaries and make a number of contributions. First, we show that it is possible to choose the size of the key-rings so that any two nodes can exchange a private key securely in the presence of a semi-honest adversary. Second, we give a protocol that achieves this guarantee and prove its security. Third, we introduce a new efficiency parameter for the EG-model that allows the protocol designer to trade-off the communication required for key establishment with the key-ring size. Finally, we propose a concrete key establishment protocol (based on the DSR protocol) that guarantees security in the presence of a semi-honest adversary.Category / Keywords: cryptographic protocols / distributed cryptography, key management, secret-key cryptography Publication Info: Under Submission Date: received 20 Oct 2008 Contact author: gelareh at umd edu Available formats: PDF | BibTeX Citation Version: 20081020:192802 (All versions of this report) Discussion forum: Show discussion | Start new discussion