Authors:
Bojan Spasić
1
;
Olivier Markowitch
2
and
Philippe Thiran
3
Affiliations:
1
Université Libre de Bruxelles, Belgium, Université de Namur, Belgium
;
2
Université Libre de Bruxelles, Belgium
;
3
Université de Namur, Belgium
Keyword(s):
Dynamic Searchable Symmetric Encryption, DSSE, Forward Privacy, Client Storage.
Abstract:
In this work, we focus on the problem of forward-private dynamic searchable symmetric encryption (DSSE) in the multi-client setting. In order to achieve forward privacy, efficient DSSE schemes require clients to store local information, such as per-keyword search counters. Such construction choices prevent these schemes from being used in a multi-user scenario. We revisit the concept of forward privacy with a goal to examine the need for client storage. As a result, we propose a new method of realising forward privacy without requiring the clients to keep any state information. Based on this method, we construct a dynamic, forward-private searchable symmetric encryption scheme supporting multiple concurrent clients with minimal overhead. The proposed construction requires no state to be kept by clients, yet provides optimal asymptotic behaviour both in time, storage and communication cost, while having similar leakage profile to other state-of-the-art DSSE schemes.