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Bayesian Networks (BNs) are an increasingly popular modelling technique in cyber security especially due to their capability to overcome data limitations. This is also instantiated by the growth of BN models development in cyber security. However, a comprehensive comparison and analysis of these models is missing. In this paper, we conduct a systematic review of the scientific literature and identify 17 standard BN models in cyber security. We analyse these models based on 9 different criteria and identify important patterns in the use of these models. A key outcome is that standard BNs are noticeably used for problems especially associated with malicious insiders. This study points out the core range of problems that were tackled using standard BN models in cyber security, and illuminates key research gaps.

Social aspects of security of information systems are often discussed in terms of “actual security��? and “perceived security��?. This may lead to the hypothesis that e-voting is controversial because in paper voting, actual and perceived security coincide, whereas they do not in electronic systems. In this paper, we argue that the distinction between actual and perceived security is problematic from a philosophical perspective, and we develop an alternative approach, based on the notion of trust. We investigate the different meanings of this notion in computer science, and link these to the philosophical work of Luhmann, who distinguishes between familiarity, confidence and trust. This analysis yields several useful distinctions for discussing trust relations with respect to information technology. We apply our framework to electronic voting, and propose some hypotheses that can possibly explain the smooth introduction of electronic voting machines in the Netherlands in the early nineties.

This paper provides a formal framework for the analysis of information hiding properties of anonymous communication protocols in terms of epistemic logic. The key ingredient is our notion of observational equivalence, which is based on the cryptographic structure of messages and relations between otherwise random looking messages. Two runs are considered observationally equivalent if a spy cannot discover any meaningful distinction between them. We illustrate our approach by proving sender anonymity and unlinkability for two anonymizing protocols, Onion Routing and Crowds. Moreover, we consider a version of Onion Routing in which we inject a subtle error and show how our framework is capable of capturing this flaw.