Towards privacy-preserving reputation management for hybrid broadcast broadband applications

Hybrid Broadcast Broadband TV (HbbTV) is an industry standard aimed to provide a platform combining TV services with Internet services, using connected TVs and set-top boxes. It enables the possibility for vendors to offer applications directly to the users, introducing new entertainment services such as streaming of video on demand, games, social networking, etc. As a consequence, tons of applications are available for users to directly download and consume through the so-called application stores, despite the potential trust and security issues arising due to the decentralized nature of these environments. Reputation management systems are usually deployed to handle trust in such dynamic scenarios, whereas they could also be used to evaluate and rate the applications from the users point of view, and even provide customized rankings. Nevertheless, they require the application stores to know information related to the installed applications and the provided recommendations of the users, hence compromising their privacy. In this paper we present a privacy-preserving reputation management framework to be integrated within the HbbTV context. We make use of identity management and extend homomorphic encryption techniques to avoid the application stores and other relying parties determining the recommendations provided by the users, yet being able to compute customized reputation values based on the similarity between users' recommendations. (C) 2014 Elsevier Ltd. All rights reserved.