Department of Computer Science and Technology

Technical reports

Secure composition of insecure components

Peter Sewell, Jan Vitek

April 1999, 44 pages

DOI: 10.48456/tr-463


Software systems are becoming heterogeneous: instead of a small number of large programs from well-established sources, a user’s desktop may now consist of many smaller components that interact in intricate ways. Some components will be downloaded from the network from sources that are only partially trusted. A user would like to know that a number of security properties hold, e.g. that personal data is not leaked to the net, but it is typically infaesible to verify that such components are well-behaved. Instead they must be executed in a secure environment, or wrapper, that provides fine-grain control of the allowable interactions between them, and between components and other system resources.

In this paper we study such wrappers, focussing on how they can be expressed in a way that enables their security properties to be stated and proved rigorously. We introduce a model programming language, the box-π calculus, that supports composition of software components and the enforcement of security policies. Several example wrappers are expressed using the calculus; we explore the delicate security properties they guarantee.

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BibTeX record

  author =	 {Sewell, Peter and Vitek, Jan},
  title = 	 {{Secure composition of insecure components}},
  year = 	 1999,
  month = 	 apr,
  url = 	 {},
  institution =  {University of Cambridge, Computer Laboratory},
  doi = 	 {10.48456/tr-463},
  number = 	 {UCAM-CL-TR-463}