Since the introduction of turbo codes in 1993, many new applications for this family of codes have been proposed. One of the latest, in the context of digital fingerprinting, is called turbo ...fingerprinting codes and was proposed by Zhang et al.. The main idea is a new fingerprinting code composed of an outer turbo code and an inner code based on the Boneh-Shaw model. The major contribution of this paper is a new analysis of this new family of codes that shows its drawbacks. These drawbacks must be considered in order to perform a correct design of a turbo fingerprinting scheme otherwise the scheme cannot retrieve the traitor users which is the main goal of digital fingerprinting scheme. Moreover, the identification of these drawbacks allows to discuss an entirely new construction of fingerprinting codes based on turbo codes.
This paper describes a cryptographic security prototype for a model of harvesting, transporting, handling and storage of logs in distributed environments. We have chosen to implement a scheme of ...identity-based cryptography (IBC), which could promisingly improve some operational aspects of the classical asymmetric models based on digital certificates. For authentication,between ends and Private Key Generators, we are using a scheme similar to One Time Password (OTP). For the prototype security we opted for a combination of symmetric and asymmetric cryptographic schemes. While the former have been used to encrypt the data, the latter has been used to protect symmetric session encryption keys. IBC concepts have been used for generation and manipulation of asymmetric keys.
Recommendation systems are information-filtering systems that help users deal with information overload. Unfortunately, current recommendation systems prompt serious privacy concerns. In this work, ...we propose an architecture that protects user privacy in such collaborative-filtering systems, in which users are profiled on the basis of their ratings. Our approach capitalizes on the combination of two perturbative techniques, namely the forgery and the suppression of ratings. In our scenario, users rate those items they have an opinion on. However, in order to avoid privacy risks, they may want to refrain from rating some of those items, and/or rate some items that do not reflect their actual preferences. On the other hand, forgery and suppression may degrade the quality of the recommendation system. Motivated by this, we describe the implementation details of the proposed architecture and present a formulation of the optimal trade-off among privacy, forgery rate and suppression rate. Finally, we provide a numerical example that illustrates our formulation.
Peer Reviewed
Provider: - Institution: - Data provided by Europeana Collections- ES El acceso a los sistemas informáticos está desde siempre ligado a la utilización de palabras de paso o passwords. Por motivos de ...seguridad, los passwords se han almacenado de forma oculta en los sistemas, siendo habitualmente el resultado de la aplicación de una función resumen -o hash- sobre el password. Dichas funciones resumen tienen una gran relevancia para el mantenimiento seguro de los passwords. También son invertibles, con una probabilidad de colisión inversamente proporcional de forma exponencial al número de bits del resumen. Una aproximación para encontrar dichas colisiones se basa en la construcción de las denominadas tablas del arco iris, que emplean una aproximación time-memory trade-off (TMTO), mostrándose eficientes a la hora de encontrar colisiones y posibilitando el acceso no autorizado a los sistemas.- CA L’accés al sistemes informàtics ha estat des-de sempre lligat a l’ús de paraules de pas o passwords. Per motius de seguretat, els passwords son emmagatzemats de forma oculta als sistemes, seguint habitualment el resultat de l’aplicació d’una funció resum -o hash- sobre el password. Aquestes funcions resum tenen una gran rellevància a l’hora de mantindre els passwords segurament. També son invertibles, amb una probabilitat de col·lisió inversament proporcional exponencialment al nombre de bits del resum. Una aproximació per a encontrar dites col·lisions son les denominades taules rainbow, que fan ús d’una aproximació time-memory trade-off (TMTO), mostrant-se eficients a l’hora d’encontrar col·lisions i possibilitant l’accés no autoritzat als sistemes.- EN Access to computer systems has always been tied to the use of passwords. For security reasons, passwords are stored in an occult manner, being usually the result of a hash function on the password. Said hash functions are highly relevant for safe-keeping passwords. They are also reversible, having a collision probability inversely proportional exponentially to the number of bits in the hash. An approximation for finding such collisions is based in the generation of the so called rainbow tables, which make use of a time-memory trade-off (TMTO), showing efficiency when looking for those collisions and allowing unauthorised access to the systems.- All metadata published by Europeana are available free of restriction under the Creative Commons CC0 1.0 Universal Public Domain Dedication. However, Europeana requests that you actively acknowledge and give attribution to all metadata sources including Europeana
