Stelios Dritsas

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The adoption of smartphones, devices transforming from simple communication devices to ‘smart’ and multipurpose devices, is constantly increasing. Amongst the main reasons are their small size, their enhanced functionality and their ability to host many useful and attractive applications. However, this vast use of mobile platforms makes them(More)
Although VoIP provides new ways of communication, at the same time it offers new possibilities for transmitting bulk unsolicited messages and calls, enabling spam over internet telephony (SPIT). The VoIP prevailing protocol is SIP, which it is vulnerable to threats that allow SPIT to be deployed. In this paper we assess the risk of identified threats and(More)
This paper addresses the issue of accommodating security requirements in application development. It proposes the use of ontologies for capturing and depicting the security experts' knowledge. In this way developers can exploit security expertise in order to make design choices that help them fulfil security requirements more effectively. We have developed(More)
Voice over Internet Protocol (VoIP) is becoming increasingly popular due to its significant advantages regarding cost and support of enhanced multimedia services. Despite of the substantial advantages of using the Internet as the transmission medium for voice calls, we can foresee many undesirable uses, especially in terms of spam. VoIP technology may(More)
Pervasive computing is expected to enter our everyday life in the foreseeable future. The capabilities of the devices, which operate in such an environment, as well as the range of services offered to the end-users are expected to be significantly increased. However, this new era is expected to have a serious effect on privacy. In this paper, we first refer(More)
While VoIP enables new means for communication, it may also provide a new way of transmitting bulk unsolicited messages and calls, namely SPam over Internet Telephony (SPIT). In this paper, we present the phases of a SPIT management process and we form a set of SPIT identification criteria, which are needed in order to characterize a call as SPIT, or a(More)