Cryptology ePrint Archive: Report 2003/197

Revisiting fully distributed proxy signature schemes

Javier Herranz and German Saez

Abstract: In a proxy signature scheme, a potential signer delegates his capabilities to a proxy signer, who can sign documents on behalf of him. The recipient of the signature verifies both identities: that of the delegator and that of the proxy signer. There are many proposals of proxy signature schemes, but security of them has not been considered in a formal way until the appearance of the work by Boldyreva et al.

If the entities which take part in a proxy signature scheme are formed by sets of participants, then we refer to it as a fully distributed proxy signature scheme.

In this work, we extend the security definitions introduced by Boldyreva et al. to the scenario of fully distributed proxy signature schemes, and we propose a specific scheme which is secure in this new model.

Category / Keywords: public-key cryptography / proxy signatures, distributed cryptography, security proofs

Date: received 24 Sep 2003

Contact author: jherranz at mat upc es

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Version: 20030924:165129 (All versions of this report)

Short URL: ia.cr/2003/197