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Differential power analysis (DPA) is a strong attack upon cryptographic devices such as smartcards. Correlation power analysis (CPA) is a specific form of DPA where the Hamming-weight and the correlation coefficient are employed. In this paper we investigate the intrinsic vulnerability of the individual operations that are targeted in DPA attacks. We find that under the typical circumstances, there is a difference in resistance to the attack between the operations. We then provide a precise definition of CPA resistance and capture it in a simple yet effective metric to rank operations. The metric is validated with both simulations and experiments on actual hardware.

Attacks on systems and organisations increasingly exploit human actors, for example through social engineering, complicating their formal treatment and automatic identification. Formalisation of human behaviour is difficult at best, and attacks on socio-technical systems are still mostly identified through brainstorming of experts. In this work we formalize attack tree generation including human factors; based on recent advances in system models we develop a technique to identify possible attacks analytically, including technical and human factors. Our systematic attack generation is based on invalidating policies in the system model by identifying possible sequences of actions that lead to an attack. The generated attacks are precise enough to illustrate the threat, and they are general enough to hide the details of individual steps.

Access control is a crucial concern to build secure IT systems and, more specifically, to protect the confidentiality of information. However, access control is necessary, but not sufficient. Actually, IT systems can manipulate data to provide services to users. The results of a data processing may disclose information concerning the objects used in the data processing itself. Therefore, the control of information flow results fundamental to guarantee data protection. In the last years many information flow control models have been proposed. However, these frameworks mainly focus on the detection and prevention of improper information leaks and do not provide support for the dynamical creation of new objects.In this paper we extend our previous work to automatically support the dynamical creation of objects by verifying the conditions under which objects can be created and automatically associating an access control policy to them. Moreover, our proposal includes mechanisms tailored to control the usage of information once it has been accessed.

The mifare Classic is a contactless smart card that is used extensively in access control for office buildings, payment systems for public transport, and other applications. We reverse engineered the security mechanisms of this chip: the authentication protocol, the symmetric cipher, and the initialization mechanism. We describe several security vulnerabilities in these mechanisms and exploit these vulnerabilities with two attacks; both are capable of retrieving the secret key from a genuine reader. The most serious one recovers the secret key from just one or two authentication attempts with a genuine reader in less than a second on ordinary hardware and without any pre-computation. Using the same methods, an attacker can also eavesdrop the communication between a tag and a reader, and decrypt the whole trace, even if it involves multiple authentications. This enables an attacker to clone a card or to restore a real card to a previous state.

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Expanded into two volumes, the Second Edition of Springers Encyclopedia of Cryptography and Security brings the latest and most comprehensive coverage of the topic: Definitive information on cryptography and information security from highly regarded researchers Effective tool for professionals in many fields and researchers of all levels Extensive resource with more than 700 contributions in Second Edition 5643 references, more than twice the number of references that appear in the First Edition With over 300 new entries, appearing in an A-Z format, the Encyclopedia of Cryptography and Security provides easy, intuitive access to information on all aspects of cryptography and security. As a critical enhancement to the First Editions base of 464 entries, the information in the Encyclopedia is relevant for researchers and professionals alike. Topics for this comprehensive reference were elected, written, and peer-reviewed by a pool of distinguished researchers in the field. The Second Editions editorial board now includes 34 scholars, which was expanded from 18 members in the First Edition. Representing the work of researchers from over 30 countries, the Encyclopedia is broad in scope, covering everything from authentication and identification to quantum cryptography and web security. The texts practical style is instructional, yet fosters investigation. Each area presents concepts, designs, and specific implementations. The highly-structured essays in this work include synonyms, a definition and discussion of the topic, bibliographies, and links to related literature. Extensive cross-references to other entries within the Encyclopedia support efficient, user-friendly searches for immediate access to relevant information. Key concepts presented in the Encyclopedia of Cryptography and Security include: Authentication and identification; Block ciphers and stream ciphers; Computational issues; Copy protection; Cryptanalysis and security; Cryptographic protocols; Electronic payment and digital certificates; Elliptic curve cryptography; Factorization algorithms and primality tests; Hash functions and MACs; Historical systems; Identity-based cryptography; Implementation aspects for smart cards and standards; Key management; Multiparty computations like voting schemes; Public key cryptography; Quantum cryptography; Secret sharing schemes; Sequences; Web Security. Topics covered: Data Structures, Cryptography and Information Theory; Data Encryption; Coding and Information Theory; Appl.Mathematics/Computational Methods of Engineering; Applications of Mathematics; Complexity. This authoritative reference will be published in two formats: print and online. The online edition features hyperlinks to cross-references, in addition to significant research.

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Over the years, formal methods have been developed for the analysis of security and privacy aspects of communication in IT systems. However, existing methods are insufficient to deal with privacy, especially in identity management (IdM), as they fail to take into account whether personal information can be linked to its data subject. In this paper, we propose a general formal method to analyze privacy of communication protocols for IdM. To express privacy, we represent knowledge of personal information in a three-layer model. We show how to deduce knowledge from observed messages and how to verify a range of privacy properties. We validate the approach by applying it to an IdM case study.

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A fundamental problem in intrusion detection is what metric(s) can be used to objectively evaluate an intrusion detection system (IDS) in terms of its ability to correctly classify events as normal or intrusive. Traditional metrics (e.g., true positive rate and false positive rate) measure different aspects, but no single metric seems sufficient to measure the capability of intrusion detection systems. The lack of a single unified metric makes it difficult to fine-tune and evaluate an IDS. In this paper, we provide an in-depth analysis of existing metrics. Specifically, we analyze a typical cost-based scheme [6], and demonstrate that this approach is very confusing and ineffective when the cost factor is not carefully selected. In addition, we provide a novel information-theoretic analysis of IDS and propose a new metric that highly complements cost-based analysis. When examining the intrusion detection process from an information-theoretic point of view, intuitively, we should have less uncertainty about the input (event data) given the IDS output (alarm data). Thus, our new metric, CI D (Intrusion Detection Capability), is defined as the ratio of the mutual information between the IDS input and output to the entropy of the input. CI D has the desired property that: (1) It takes into account all the important aspects of detection capability naturally, i.e., true positive rate, false positive rate, positive predictive value, negative predictive value, and base rate; (2) it objectively provides an intrinsic measure of intrusion detection capability; and (3) it is sensitive to IDS operation parameters such as true positive rate and false positive rate, which can demonstrate the effect of the subtle changes of intrusion detection systems. We propose CI D as an appropriate performance measure to maximize when fine-tuning an IDS. The obtained operation point is the best that can be achieved by the IDS in terms of its intrinsic ability to classify input data. We use numerical examples as well as experiments of actual IDSs on various data sets to show that by using CI D, we can choose the best (optimal) operating point for an IDS and objectively compare different IDSs.

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This article presents a technique to incrementally maintain materializations of ontological entailments. Materialization consists in precomputing and storing a set of implicit entailments, such that frequent and/or crucial queries to the ontology can be solved more efficiently. The central problem that arises with materialization is its maintenance when axioms change, viz. the process of propagating changes in explicit axioms to the stored implicit entailments. When considering rule-enabled ontology languages that are operationalized in logic databases, we can distinguish two types of changes. Changes to the ontology will typically manifest themselves in changes to the rules of the logic program, whereas changes to facts will typically lead to changes in the extensions of logical predicates. The incremental maintenance of the latter type of changes has been studied extensively in the deductive database context and we apply the technique proposed in [30] for our purpose. The former type of changes has, however, not been tackled before. In this article we elaborate on our previous papers [32, 33], which extend the approach of [30] to deal with changes in the logic program. Our approach is not limited to a particular ontology language but can be generally applied to arbitrary ontology languages that can be translated to Datalog programs, i.e. such as O-Telos, F-Logic [16] RDF(S), or Description Logic Programs [34]. © Springer-Verlag Berlin Heidelberg 2004.