Computability on quasi-Polish spaces

International audienceWe investigate the effectivizations of several equivalent definitions of quasi-Polish spaces and study which characterizations hold effectively. Being a computable effectively open image of the Baire space is a robust notion that admits several characterizations. We show that some natural effectivizations of quasi-metric spaces are strictly stronger

The notion of exhaustiveness and Ascoli-type theorems

In this paper we introduce the notion of exhaustiveness which applies for both families and nets of functions. This new notion is close to equicontinuity and describes the relation between pointwise convergence for functions and α-convergence (continuous convergence). Using these results we obtain some Ascoli-type theorems dealing with exhaustiveness instead of equicontinuity. Also we deal with the corresponding notions of separate exhaustiveness and separate α-convergence. Finally we give conditions under which the pointwise limit of a sequence of arbitrary functions is a continuous function. © 2008 Elsevier B.V. All rights reserved

Internationalising the Management Information Systems Module.

The work described here draws on the emergent need to internationalise the curriculum in higher education. The paper in particular focuses on the internationalisation of the Management Information Systems (MIS) module and the identification of learning differences among the two dominant cultural groups in higher education in the UK: Asian and European students. The identification of differences among knowledge patterns of these cultural groups is achieved through the application of a concept mapping technique. The research question addressed is: How can we internationalise the MIS module's content and teaching methods to provide for students from different cultural backgrounds

Authentication with RIPEMD-160 and other alternatives: A Hardware Design Perspective 103 X Authentication with RIPEMD-160 and other alternatives: A Hardware Design Perspective

Abstract Taking into consideration the rapid evolution of communication standards that include message authentication and integrity verification, it is realized that constructions like MAC and HMAC, are widely used in the most popular cryptographic schemes since provision of a way to check the integrity of information transmitted over or stored in an unreliable medium is a prime necessity in the world of open computing and communications. MACs are used so as to protect both a message's integrity as well as its authenticity, by allowing verifiers (who also possess the secret key) to detect any changes to the message content. In every modern cryptographic scheme that is used to secure a crucial application that calls for security, a keyed-hash message authentication code, or HMAC, is incorporated. Beyond HMAC, a block cipher algorithm is also incorporated (i.e like AES), thus resulting to the whole security scheme. The proposed hardware design invokes a number of optimizing techniques like pipeline, evaluation-based partial unrolling, certain algorithmic transformations in space and time and computational re-ordering, leading to a highthroughput and low-power design for the whole HMAC construction. Finally, a new algorithm, CMAC, for producing message authenticating codes (MACs) which was recently proposed by NIST, is also described. The proposed security scheme incorporates a FIPS approved and a secure block cipher algorithm (that might have already been deployed in the security scheme) and was standardized by NIST in May, 2005. This work concludes with an efficient hardware implementation of the CMAC standard

Authentication with RIPEMD-160 and other alternatives: A Hardware Design Perspective

Taking into consideration the rapid evolution of communication standards that include message authentication and integrity verification, it is realized that constructions like MAC and HMAC, are widely used in the most popular cryptographic schemes since provision of a way to check the integrity of information transmitted over or stored in an unreliable medium is a prime necessity in the world of open computing and communications. MACs are used so as to protect both a message's integrity as well as its authenticity, by allowing verifiers (who also possess the secret key) to detect any changes to the message content. In every modern cryptographic scheme that is used to secure a crucial application that calls for security, a keyed-hash message authentication code, or HMAC, is incorporated. Beyond HMAC, a block cipher algorithm is also incorporated (i.e like AES), thus resulting to the whole security scheme. The proposed hardware design invokes a number of optimizing techniques like pipeline, evaluation-based partial unrolling, certain algorithmic transformations in space and time and computational re-ordering, leading to a highthroughput and low-power design for the whole HMAC construction. Finally, a new algorithm, CMAC, for producing message authenticating codes (MACs) which was recently proposed by NIST, is also described. The proposed security scheme incorporates a FIPS approved and a secure block cipher algorithm (that might have already been deployed in the security scheme) and was standardized by NIST in May, 2005. This work concludes with an efficient hardware implementation of the CMAC standard