Secure protocols with asymmetric trust.
In: Kurosawa, K, (ed.)
ADVANCES IN CRYPTOLOGY - ASIACRYPT 2007.
(pp. 357 - 375).
In the standard general-adversary model for multi-party protocols, a global adversary structure is given, and every party must trust in this particular structure. We introduce a more general model, the asymmetric-trust model, wherein every party is allowed to trust in a different, personally customized adversary structure. We have two main contributions. First, we present non-trivial lower and upper bounds for broadcast, verifiable secret sharing, and general multi-party computation in different variations of this new model. The obtained bounds demonstrate that the new model is strictly more powerful than the standard general-adversary model. Second, we propose a framework for expressing and analyzing asymmetric trust in the usual simulation paradigm for defining security of protocols, and in particular show a general composition theorem for protocols with asymmetric trust.
|Title:||Secure protocols with asymmetric trust|
|Event:||13th International Conference on Theory and Application of Cryptology and Information Security|
|Dates:||2007-12-02 - 2007-12-06|
|Keywords:||MULTIPARTY COMPUTATION, AGREEMENT|
|UCL classification:||UCL > School of BEAMS
UCL > School of BEAMS > Faculty of Engineering Science
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