Tests for Establishing Security Properties

Ensuring strong security properties in some cases requires participants to carry out tests during the execution of a protocol. A classical example is electronic voting: participants are required to verify the presence of their ballots on a bulletin board, and to verify the computation of the election outcome. The notion of certificate transparency is another example, in which participants in the protocol are required to perform tests to verify the integrity of a certificate log. We present a framework for modelling systems with such `testable properties', using the applied pi calculus. We model the tests that are made by participants in order to obtain the security properties. Underlying our work is an attacker model called ``malicious but cautious'', which lies in between the Dolev-Yao model and the ``honest but curious'' model. The malicious-but-cautious model is appropriate for cloud computing providers that are potentially malicious but are assumed to be cautious about launching attacks that might cause user tests to fail

Composing security protocols: from confidentiality to privacy

Security protocols are used in many of our daily-life applications, and our privacy largely depends on their design. Formal verification techniques have proved their usefulness to analyse these protocols, but they become so complex that modular techniques have to be developed. We propose several results to safely compose security protocols. We consider arbitrary primitives modeled using an equational theory, and a rich process algebra close to the applied pi calculus. Relying on these composition results, we derive some security properties on a protocol from the security analysis performed on each of its sub-protocols individually. We consider parallel composition and the case of key-exchange protocols. Our results apply to deal with confidentiality but also privacy-type properties (e.g. anonymity) expressed using a notion of equivalence. We illustrate the usefulness of our composition results on protocols from the 3G phone application and electronic passport

eIDeCert: a user-centric solution for mobile identification

The necessity to certify one's identity for different purposes and the evolution of mobile technologies have led to the generation of electronic devices such as smart cards, and electronic identities designed to meet daily needs. Nevertheless, these mechanisms have a problem: they don't allow the user to set the scope of the information presented. That problem introduces interesting security and privacy challenges and requires the development of a new tool that supports user-centrity for the information being handled. This article presents eIDeCert, a tool for the management of electronic identities (eIDs) in a mobile environment with a user-centric approach. Taking advantage of existing eCert technology we will be able to solve a real problem. On the other hand, the application takes us to the boundary of what the technology can cope with: we will assess how close we are to the boundary, and we will present an idea of what the next step should be to enable us to reach the goal

Lengths May Break Privacy – Or How to Check for Equivalences with Length

Security protocols have been successfully analyzed using symbolic models, where messages are represented by terms and protocols by processes. Privacy properties like anonymity or untraceability are typically expressed as equivalence between processes. While some decision procedures have been proposed for automatically deciding process equivalence, all existing approaches abstract away the information an attacker may get when observing the length of messages. In this paper, we study process equivalence with length tests. We first show that, in the static case, almost all existing decidability results (for static equivalence) can be extended to cope with length tests. In the active case, we prove decidability of trace equivalence with length tests, for a bounded number of sessions and for standard primitives. Our result relies on a previous decidability result from Cheval et al (without length tests). Our procedure has been implemented and we have discovered a new flaw against privacy in the biometric passport protocol

Encryption – use and control in E-commerce

The author describes how cryptography can be used to address modern business requirements such as identity protection, secure web access and digital signatures. Article by Robert Bond (Head of Innovation & Technology Group, Hobson Audley and Fellow of SALS). Published in Amicus Curiae - Journal of the Institute of Advanced Legal Studies and its Society for Advanced Legal Studies. The Journal is produced by the Society for Advanced Legal Studies at the Institute of Advanced Legal Studies, University of London