Ecole d'ingénieur et centre de recherche en Sciences du numérique

Provably secure policy-based cryptography

Bagga, Walid;Molva, Refik

Research report RR-05-141

The concept of policy-based cryptography (PBC) is a promising paradigm for trust establishment and authorization in large-scale open environments. A policy-based encryption scheme (PBE) allows to encrypt a message according to a policy so that only entities fulfilling the policy are able to perform the decryption of the message. Symmetrically, a policy-based signature scheme (PBS) assures that only entities fulfilling a given policy are able to generate a valid signature according to the policy. Existing PBC schemes suffer from either inefficiency or lack of strong security arguments. In this paper, we introduce policy-oriented strong security models for PBE and PBS schemes. Then, we present concrete and elegant PBE and PBS schemes from bilinear pairings. Our schemes are not only at least as efficient as existing schemes, but also, and more importantly, provably secure under the defined security models.

Document Bibtex

Titre:Provably secure policy-based cryptography
Mots Clés:access structures;authorization;trust establishment;bilinear pairings;provable security
Département:Sécurité numérique
Eurecom ref:1677
Copyright: © EURECOM. Personal use of this material is permitted. The definitive version of this paper was published in Research report RR-05-141 and is available at :
Bibtex: @techreport{EURECOM+1677, year = {2005}, title = {{P}rovably secure policy-based cryptography}, author = {{B}agga, {W}alid and {M}olva, {R}efik}, number = {EURECOM+1677}, month = {05}, institution = {Eurecom}, url = {},, }
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