Constantinos Patsakis

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In this paper it is described how can a social network, like Facebook, be exploited and converted into an attack platform, in order to gain some sensitive data, which can complete a perfect attacking profile against a user. More specifically, we created a Facebook application for demonstration purposes that on the surface is a simple application, but on the(More)
SAT solvers are being used more and more in Cryptanalysis, with mixed results regarding their e ciency, depending on the structure of the algorithm they are applied. However, when it comes to integer factorization, or more specially the RSA problem, SAT solvers prove to be at least ine cient. The running times are too long to be compared with any well known(More)
This article proposes a new technique for Privacy Preserving Collaborative Filtering (PPCF) based on microaggregation, which provides accurate recommendations estimated from perturbed data whilst guaranteeing user k-anonymity. The experimental results presented in this article show the effectiveness of the proposed technique in protecting users’ privacy(More)
Due to the rise of social media, several new needs, problems and challenges have emerged in users' privacy and security policies. Two very serious problems that should be addressed are identity theft and unauthorized content sharing. In this work we propose a more secure scheme for privacy in social networks by the use of watermarking that manages to(More)
The wide adoption of smart phones has enabled Online Social Networks (OSN) to exploit the location awareness capabilities offering users better interaction and context aware content. While these features are very attractive, the publication of users’ location in an OSN exposes them to privacy hazards. Recently, various protocols have been proposed for(More)
The unprecedented urbanization of the past decades has not only led to the introduction of the concept of smart cities, but has simultaneously made them a necessity. By converting our cities into smart ones, we enable future generations to live in a friendly and sustainable environment. Within smart cities, the wide deployment of sensors allows the(More)
Automatic recommender systems have become a cornerstone of e-commerce, especially after the great welcome of Web 2.0 based on participation and interaction of Internet users. Collaborative Filtering (CF) is a recommender system that is becoming increasingly relevant for the industry due to the growth of the Internet, which has made it much more difficult to(More)