Multi-user searchable encryption in the cloud

Van Rompay, Cédric; Molva, Refik; Önen, Melek
Research Report RR-15-306

While Searchable Encryption (SE) has been widely studied, adapting it to the
multi-user setting whereby many users can upload secret files or documents and
delegate search operations to multiple other users still remains an interesting problem.
In this paper we show that the adversarial models used in existing multi-user
searchable encryption solutions are not realistic as they implicitly require that the
cloud service provider cannot collude with some users. We then propose a stronger
adversarial model, and propose a construction which is both practical and provably
secure in this new model. The new solution combines the use of bilinear pairings
with private information retrieval and introduces a new, non trusted entity called
"proxy" to transform each user's search query into one instance per targeted file or
document.

Type:
Rapport
Date:
2015-08-21
Department:
Sécurité numérique
Eurecom Ref:
4659
Copyright:
© EURECOM. Personal use of this material is permitted. The definitive version of this paper was published in Research Report RR-15-306 and is available at :

PERMALINK : https://www.eurecom.fr/publication/4659