Catálogo de publicaciones - libros

This paper presents a case in the development of a knowledge community support system in the context of an industrial association group in the construction sector. This system is a result of the Know-Construct project which aims at providing association sponsored SME communities of the construction sector with a sophisticated information management platform and community building tools for knowledge sharing. The paper begins by characterizing the so-called construction industry knowledge community. The Know-Construct system concept and the its general architecture are described, focusing on the semantic resources, in particular the ontologies structure. The final part of the paper depicts the approach to the actual introduction of the system in the community. An action-research approach was planned to obtain research results regarding the social acceptance of semantic resources such as the ontologies and technical classifications used in system.

This paper aims at showing how beneficial it is to use an analysis grid as a guide to evaluate the dynamics of an online community and, on the basis of this grid, to develop agent-based models to explore each of the dimensions characterizing online communities within this grid. Several models from different perspectives have been proposed to study the dynamics of online communities (socio-technical perspective, life stages perspective...). In this paper, we consider two dimensions to evaluate them: the informational one and the social one. Their constituents are derived from an empirical analysis and a review of the literature on online communities and reputation.

On behalf of the Program Committee of the First International Workshop on Information Security (IS 2006), it was our great pleasure to welcome the participants to the IS 2006, held in conjunction with OnTheMove Federated Conferences (OTM 2006), from October 30 to November 1, 2006, in Montpellier, France. In recent years, significant advances in information security have been made throughout the world. The objective of the workshop was to promote information security related research and development activities and to encourage communication between researchers and engineers throughout the world in this area.

Content providers and distributors need to have secured and trusted systems for the distribution of multimedia content with Digital Rights Management (DRM) to ensure the revenues derived from their works. This paper discusses the security mechanisms applied to the implementation of a DRM architecture, regarding the certification and verification of user tools integrity during their whole life cycle, the mechanisms for providing a secure and trusted communication between client tools and the server framework for authorisation, certification or verification purposes, and the mechanisms for the secure storage and resynchronisation of the reports that describe the actions performed by users during the tool offline operation. The presented architecture is being implemented in the AXMEDIS project, which aims to create an innovative technology framework for the automatic production, protection and distribution of digital cross media contents over a range of different media channels, including PC (on the Internet), PDA, kiosks, mobile phones and i-TV.

When communicating secret information there is more than one route to follow to ensure the confidentiality of the message being transmitted. Encryption might be an obvious choice; however there are limitations and disadvantages to using encryption. An alternative approach is steganography, which is a technology for hiding information in other information. Combining the two disciplines may provide better security but more overhead, since the receiver must now have knowledge not only of how the information was encrypted, but also of how it was hidden, in order to retrieve the message. This paper proposes a system where image steganography is combined with encryption by hiding not only a message inside an image, but also the means to extract and decrypt the message. An executable program is hidden inside the image that functions as a decryptor, enabling the receiver to be oblivious to the encryption algorithm used.

Resolving rightful ownerships of digital images is an active research area of watermarking. Though a watermark is used to prove the owner’s ownership, an attacker can invalidate it by creating his fake original image and its corresponding watermark. This kind of attack is called ambiguity attack and can be tackled either by use of non-invertible watermarking schemes or by use of zero-knowledge watermark detections. If a non-invertible watermarking scheme is used, then the owner should reveal her original image which should be kept secret. And if a zero-knowledge watermark detection is used, then no one can verify the claimed ownership unless the owner is involved. Moreover, in case of zero-knowledge watermark detection, the protocol is relatively complicated and needs more computations. In this paper, using the MSBs string of the original image other than the original image itself, we propose an efficient dispute resolving method while preserving secrecy of the original image.

RFID tags are devices of very limited computational capabilities, which only have 250-3K logic gates that can be devoted to security-related tasks. Many proposals have recently appeared, but all of them are based on RFID tags using classical cryptographic primitives such as PRNGs, hash functions, block ciphers, etc. We believe this assumption to be fairly unrealistic, as classical cryptographic constructions lie well beyond the computational reach of very low-cost RFID tags. A new approach is necessary to tackle this problem, so we propose an extremely efficient lightweight mutual-authentication protocol that offers an adequate security level for certain applications and can be implemented even in the most limited low-cost RFID tags, as it only needs around 150 gates.

Radio Frequency Identification (RFID) system is an important technology in ubiquitous computing environment. RFID system should be compatible with most RFID system applications to support the ubiquitous computing environment. Recently, researchers had studied about RFID standardization. After all, EPCglobal Class-1 Gen-2 (C1G2) RFID is selected as an international standard of RFID systems. Unfortunately, it has fatal security problems to be vulnerable to information leakage and traceability since a tag of EPCglobal C1G2 emits its fixed ID(EPC) without hiding or modifying. A main goal of our work is to propose the secure protocol well suitable for EPCglobal C1G2. First of all, our protocol exactly follows RFID standard with only current capabilities of a tag approved in the standard, assuring that our protocol is secure against impersonation, information leakage, and traceability etc.

Designers of RFID security protocols can choose between a wide variety of cryptographic algorithms. However, when implementing these algorithms on RFID tags fierce constraints have to be considered. Looking at the common assumption in the literature that hash functions are implementable in a manner suitable for RFID tags and thus heavily used by RFID security protocol designers we claim the following. Current standards and state-of-the-art low-power implementation techniques favor the use of block ciphers like the Advanced Encryption Standard (AES) instead of hash functions from the SHA family as building blocks for RFID security protocols. In turn, we present a low-power architecture for the widely recommended hash function SHA-256 which is the basis for the smallest and most energy-efficient ASIC implementation published so far. To back up our claim we compare the achieved results with the smallest available AES implementation. The AES module requires only a third of the chip area and half of the mean power. Our conclusions are even stronger since we can show that smaller hash functions like SHA-1, MD5 and MD4 are also less suitable for RFID tags than the AES. Our analysis of the reasons of this result gives some input for future hash function designs.

There is a strong consensus about the need for IPsec, although its use is not widespread for end-to-end communications. One of the main reasons for this is the difficulty for authenticating two end-hosts that do not share a secret or do not rely on a common Certification Authority. In this paper we propose a modification to IKE to use reverse DNS and DNSSEC (named DNSSEC-to-IKE) to provide end-to-end authentication to Internet hosts that do not share any secret, without requiring the deployment of a new infrastructure. We perform a comparative analysis in terms of requirements, provided security and performance with state-of-the-art IKE authentication methods and with a recent proposal for IPv6 based on CGA. We conclude that DNSSEC-to-IKE enables the use of IPsec in a broad range of scenarios in which it was not applicable, at the price of offering slightly less security and incurring in higher performance costs.