Privacy by typing in the $\pi$-calculus

Abstract

In this paper we propose a formal framework for studying privacy in information systems. The proposal follows a two-axes schema where the first axis considers privacy as a taxonomy of rights and the second axis involves the ways an information system stores and manipulates information. We develop a correspondence between the schema above and an associated model of computation. In particular, we propose the Privacy calculus, a calculus based on the π-calculus with groups extended with constructs for reasoning about private data. The privacy requirements of an information system are captured via a privacy policy language. The correspondence between the privacy model and the Privacy calculus semantics is established using a type system for the calculus and a satisfiability definition between types and privacy policies. We deploy a type preservation theorem to show that a system respects a policy and it is safe if the typing of the system satisfies the policy. We illustrate our methodology via analysis of two use cases: a privacy-aware scheme for electronic traffic pricing and a privacy-preserving technique for speed-limit enforcement. LOGICAL METHODS lI N COMPUTER SCIENCE

The Cpi-calculus: a Model for Confidential Name Passing

“…The notion of secrecy has been studied intensively in process calculi in the past and the variety of techniques have been proposed. The most related to our work are process models building on the π-calculus, such as [1,5,2,10,7,19].…”

“…The group creation construct blocks communications of channels that are declared as members of the group outside the initial scope of the group, hence preventing the leakage of protected channels. Kouzapas and Philippou [10] extend the model of π-calculus with groups by constructs that allow reasoning about the private data in information systems. The work of Giunti et.…”

“…On the other hand, new technologies can also provide new ways to deal with privacy problems [17]. According to Solove [16], there are four types of privacy violation: invasions, information collection, information processing, and information dissemination (see also [10]). The focus of this paper will be on presenting the techniques for controlling information dissemination in distributed systems.…”