2009
Authors
Barbosa, M; Moss, A; Page, D;
Publication
JOURNAL OF CRYPTOLOGY
Abstract
Although cryptographic software implementation is often performed by expert programmers, the range of performance and security driven options, as well as more mundane software engineering issues, still make it a challenge. The use of domain specific language and compiler techniques to assist in description and optimisation of cryptographic software is an interesting research challenge. In this paper we investigate two aspects of such techniques, focusing on Elliptic Curve Cryptography (ECC) in particular. Our constructive results show that a suitable language allows description of ECC based software in a manner close to the original mathematics; the corresponding compiler allows automatic production of an executable whose performance is competitive with that of a hand-optimised implementation. In contrast, we study the worrying potential for na < ve compiler driven optimisation to render cryptographic software insecure. Both aspects of our work are set within the context of CACE, an ongoing EU funded project on this general topic.
2009
Authors
Barbosa, M; Farshim, P;
Publication
PROGRESS IN CRYPTOLOGY - AFRICACRYPT 2009
Abstract
We propose a generic modelling technique that can be used to extend existing frameworks for theoretical security analysis in order to capture the use of timestamps. We apply this technique to two of the most popular models adopted in literature (Bellare-Rogaway and Canetti-Krawczyk). We analyse previous results obtained using these models in light of the proposed extensions, and demonstrate their application to a new class of protocols. In the timed CK model we concentrate on modular design and analysis of protocols, and propose a more efficient timed authenticator relying on timestamps. The structure of this new authenticator implies that an authentication mechanism standardised in ISO-9798 is secure. Finally, we use our timed extension to the BR model to establish the security of an efficient ISO protocol for key transport and unilateral entity authentication.
2009
Authors
Frade, MJ; Saabas, A; Uustalu, T;
Publication
Proceedings of the 2009 ACM SIGPLAN Symposium on Partial Evaluation and Program Manipulation, PEPM'09
Abstract
We show that a wide class of bidirectional data-flow analyses and program optimizations based on them admit declarative descriptions in the form of type systems. The salient feature is a clear separation between what constitutes a valid analysis and how the strongest one can be computed (via the type checking versus principal type inference distinction). The approach also facilitates elegant relational semantic soundness definitions and proofs for analyses and optimizations, with an application to mechanical transformation of program proofs, useful in proof-carrying code. Unidirectional forward and backward analyses are covered as special cases; the technicalities in the general bidirectional case arise from more subtle notions of valid and principal types. To demonstrate the viability of the approach we consider two examples that are inherently bidirectional: type inference (seen as a data-flow problem) for a structured language where the type of a variable may change over a program's run and the analysis underlying a stack usage optimization for a stack-based low-level language. ©2009 ACM.
2009
Authors
Ferreira, PG; Silva, CG; Azevedo, PJ; Brito, RMM;
Publication
COMPUTATIONAL INTELLIGENCE METHODS FOR BIOINFORMATICS AND BIOSTATISTICS
Abstract
Molecular dynamics simulations is a valuable tool to study protein unfolding in silico. Analyzing the relative spatial position of the residues during the simulation may indicate which residues are essential in determining the protein structure. We present a method, inspired by a popular data mining technique called Frequent Itemset Mining, that clusters sets of amino acid residues with a synchronized trajectory during the unfolding process. The proposed approach has several advantages over traditional hierarchical clustering. © 2009 Springer Berlin Heidelberg.
2009
Authors
Ferreira, PG; Azevedo, PJ;
Publication
Handbook of Research on Machine Learning Applications and Trends: Algorithms, Methods, and Techniques
Abstract
The recent increase in the number of complete genetic sequences freely available through specialized Internet databases presents big challenges for the research community. One such challenge is the efficient and effective search of sequence patterns, also known as motifs, among a set of related genetic sequences. Such patterns describe regions that may provide important insights about the structural and functional role of DNA and proteins. Two main classes can be considered: probabilistic patterns represent a model that simulates the sequences or part of the sequences under consideration and deterministic patterns that either match or not the input sequences. In this chapter a general overview of deterministic sequence mining over sets of genetic sequences is proposed. The authors formulate an architecture that divides the mining process workflow into a set of blocks. Each of these blocks is discussed individually. © 2010, IGI Global.
2009
Authors
Silva, CG; Ferreira, PG; Azevedo, PJ; Brito, RMM;
Publication
Evolving Application Domains of Data Warehousing and Mining: Trends and Solutions
Abstract
The protein folding problem, i.e. the identification of the rules that determine the acquisition of the native, functional, three-dimensional structure of a protein from its linear sequence of amino-acids, still is a major challenge in structural molecular biology. Moreover, the identification of a series of neurodegenerative diseases as protein unfolding/misfolding disorders highlights the importance of a detailed characterisation of the molecular events driving the unfolding and misfolding processes in proteins. One way of exploring these processes is through the use of molecular dynamics simulations. The analysis and comparison of the enormous amount of data generated by multiple protein folding or unfolding simulations is not a trivial task, presenting many interesting challenges to the data mining community. Considering the central role of the hydrophobic effect in protein folding, we show here the application of two data mining methods - hierarchical clustering and association rules - for the analysis and comparison of the solvent accessible surface area (SASA) variation profiles of each one of the 127 amino-acid residues in the amyloidogenic protein Transthyretin, across multiple molecular dynamics protein unfolding simulations. © 2010, IGI Global.
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