FMSD12

F. Cassez, J. Dubreil, H. Marchand. Synthesis of Opaque Systems with Static and Dynamic Masks. Formal Methods in System Design, 40(1):88-115, 2012.

Download [help]

Download paper: Doi page

Download paper: Adobe portable document (pdf)

Copyright notice: This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. These works may not be reposted without the explicit permission of the copyright holder.
This page is automatically generated by bib2html v216, © INRIA 2002-2007, Projet Lagadic

Abstract

Opacity is a security property formalizing the absence of secret information leakage and we address in this paper the problem of synthesizing opaque systems. A secret predicate S over the runs of a system G is opaque to an external user having partial observability over G, if s/he can never infer from the observation of a run of G that the run belongs to S. We choose to control the observability of events by adding a device, called a mask, between the system G and the users. We first investigate the case of static partial observability where the set of events the user can observe is fixed a priori by a static mask. In this context, we show that checking whether a system is opaque is PSPACE-complete, which implies that computing an optimal static mask ensuring opacity is also a PSPACE-complete problem. Next, we introduce dynamic partial observability where the set of events the user can observe changes over time and is chosen by a dynamic mask. We show how to check that a system is opaque w.r.t. to a dynamic mask and also address the corresponding synthesis problem: given a system G and secret states S, compute the set of dynamic masks under which S is opaque. Our main result is that the set of such masks can be finitely represented and can be computed in EXPTIME and this is a lower bound. Finally we also address the problem of computing an optimal mask

Contact

Jérémy Dubreil
Hervé Marchand http://www.irisa.fr/prive/hmarchan

BibTex Reference

@article{FMSD12,
   Author = {Cassez, F. and Dubreil, J. and Marchand, H.},
   Title = {Synthesis of Opaque Systems with Static and Dynamic Masks},
   Journal = {Formal Methods in System Design},
   Volume = {40},
   Number = {1},
   Pages = {88--115},
   Year = {2012}
}

EndNote Reference [help]

Get EndNote Reference (.ref)