Approximate non-interference

  • Authors:
  • Alessandra Di Pierro;Chris Hankin;Herbert Wiklicky

  • Affiliations:
  • (Correspd. Tel.: +39 05 02212779/ Fax: +39 05 02212726/ E-mail: dipierro@di.unipi.it) Dipartimento di Informatica, Università/ di Pisa, Italy E-mail: dipierro@di.unipi.it;Department of Computing, Imperial College London, UK E-mail: {clh,herbert}@doc.ic.ac.uk;Department of Computing, Imperial College London, UK E-mail: {clh,herbert}@doc.ic.ac.uk

  • Venue:
  • Journal of Computer Security - Special issue on WITS'02
  • Year:
  • 2004

Quantified Score

Hi-index 0.00

Visualization

Abstract

We address the problem of characterising the security of a program against unauthorised information flows. Classical approaches are based on non-interference models which depend ultimately on the notion of process equivalence. In these models confidentiality is an absolute property stating the absence of any illegal information flow. We present a model in which the notion of non-interference is approximated in the sense that it allows for some exactly quantified leakage of information. This is characterised via a notion of process similarity which replaces the indistinguishability of processes by a quantitative measure of their behavioural difference. Such a quantity is related to the number of statistical tests needed to distinguish two behaviours. We also present two semantics-based analyses of approximate non-interference and we show that one is a correct abstraction of the other.