Constantinos Delakouridis

Enabling Collaborative Medical Diagnosis Over the Internet via Peer-to-Peer Distribution of Electronic Health Records

Recent developments in networking and computing technologies and the expansion of the electronic health record system have enabled the possibility of online collaboration between geographically distributed medical personnel. In this context, the paper presents a Web-based application, which implements a collaborative working environment for physicians by enabling the peer-to-peer exchange of electronic health records. The paper treats technological issues such as Video, Audio and Message Communication, Workspace Management, Distributed Medical Data Management and exchange, while it emphasizes on the Security issues arisen, due to the sensitive and private nature of the medical information. In the paper, we present initial results from the system in practice and measurements regarding transmission times and bandwidth requirements. A wavelet based image compression scheme is also introduced for reducing network delays. A number of physicians were asked to use the platform for testing purposes and for measuring user acceptance. The system was considered by them to be very useful, as they found that the platform simulated very well the personal contact between them and their colleagues during medical meetings.

Cognitive Spectrum and Its Security Issues

The current trend for opportunistic use of the licensed or licensed-exempt wireless spectrum with limited rules, or even without rules, introduces significant scientific and technical challenges for the networks of the future. Until now, for the realization of the cognitive radio paradigm, several spectrum sharing schemes have been proposed, such as centralized and distributed schemes, and cooperative or noncooperative spectrum sharing mechanisms. Unfortunately, some of the existing proposals for spectrum sharing and management introduce significant security leakages, putting into effect unfairness, unavailability, and selfishness, or even malicious behaviors. Additionally, the identification, recording and reporting of selfish, free-riders, malicious and anomalous actions by peers is still an open issue in the majority of the existing spectrum management schemes. This paper discusses and classifies the weak points and the vulnerabilities of the spectrum sharing mechanisms.

Share the secret: enabling location privacy in ubiquitous environments

Anonymity and location privacy in mobile and pervasive environments has been receiving increasing attention during the last few years, and several mechanisms and architectures have been proposed to prevent “big brother” phenomena. In this paper we present a novel architecture to shield the location of a mobile user and preserve the anonymity on the service delivery. This architecture, called “Share the Secret – STS”, uses totally un-trusted entities to distribute portions of anonymous location information, and authorizes other entities to combine these portions and derive the location of a user. STS simply divides the secret, and as a lightweight scheme it can be applied to network of nodes illustrating low processing and computational power, such as nodes of an ad-hoc network, smart gadgets and sensors.

iHIDE: hiding sources of information in WSNs

In the most deployment scenarios of wireless sensor networks (WSNs) the sensors are statically distributed and configured to propagate the captured information towards the sink-sensor. This information might be unclassified, such as environmental data, or private, such as the location of an important asset. In the latter case, security mechanisms might be essential to ensure the confidentiality of the location of the information source. Such mechanisms might exploit light cryptographic systems, such us elliptic curve, to authenticate and cipher the information that is relayed towards the sink. On the other hand, the static configuration of WSNs might simplify the apocalypses of the information source. An eavesdropper might use reverse packet-routing engineering to expose the location of the sensor that captured and reported the phenomenon. To deal with this issue, we have introduced a novel approach, called iHIDE - information hiding in distributing environments, to enable source-location privacy in WSNs. iHIDE adopts a non-geographical, overlay routing method for packet delivery. This paper introduces the architecture, and assesses its performance through simulation experiments, providing comparisons with relative approaches

Providing anonymity services in SIP

Anonymity in telecommunication services means much more than protecting the identity of participants. It requires mechanisms and protocols that unlink the communication parties, unlink users from their location, and avoid statistical analysis. These functional requirements apply also when providing anonymity services to SIP, whereas the identities of caller and the callee(s) should be secured. On the other hand, SIP introduces additional functional requirements to any anonymity services, such as time limitations for session establishment, involvement of several functional entities, inter-domain communications and support of streaming services when the call is established. Here, we propose the usage of a privacy enhancement framework, called Mist, as a solution to the anonymity issue in SIP. For achieving anonymity, the original Mist architecture was modified to be adapted in the SIP framework. The paper discusses how Mist can be adapted to SIP and efficiently support anonymity features.

An incentive-based architecture to enable privacy in dynamic environments

Purpose – The purpose of this paper is to propose the use of priority‐based incentives for collaborative hiding of confidential information in dynamic environments, such as self‐organized networks, peer‐to‐peer systems, pervasive and grid computing applications.Design/methodology/approach – The paper documents the necessity of ISSON (Incentives for Secret‐sharing in Self‐Organised Networks); it provides functional and technical details on the proposed architecture; and, it assesses its feasibility in mobile ad‐hoc networks through real experiments. The paper elaborates on the availability of the hidden information through an analytical framework.Findings – Through the real experiments, ISSON was found to be efficient in terms of communication and processing costs. Additionally, it avoids collusions for unauthorized revealing of the hidden information, and ensures the unlinkability and availability of the secret when it is divided and stored to peers.Originality/value – The proposed, incentive‐based, priva...