Departmental Papers (CIS)

Date of this Version

June 2006

Document Type

Conference Paper


From the 33rd International Colloquium, ICALP 2006, Venice, Italy, July 10-14, 2006, Proceedings, Part II.


We propose a general framework of secrecy and preservation of secrecy for labeled transition systems. Our definition of secrecy is parameterized by the distinguishing power of the observer, the properties to be kept secret, and the executions of interest, and captures a multitude of definitions in the literature. We define a notion of secrecy preserving refinement between systems by strengthening the classical trace-based refinement so that the implementation leaks a secret only when the specification also leaks it. We show that secrecy is in general not definable in µ-calculus, and thus not expressible in specification logics supported by standard model-checkers. However, we develop a simulation-based proof technique for establishing secrecy preserving refinement. This result shows how existing refinement checkers can be used to show correctness of an implementation with respect to a specification.

Subject Area

CPS Formal Methods

Publication Source

Lecture Notes in Computer Science: Automata, Languages and Programming



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Date Posted: 04 December 2006

This document has been peer reviewed.