Using quantum key distribution for cryptographic purposes: a survey

The appealing feature of quantum key distribution (QKD), from a cryptographic viewpoint, is the ability to prove the information-theoretic security (ITS) of the established keys. As a key establishment primitive, QKD however does not provide a standalone security service in its own: the secret keys established by QKD are in general then used by a subsequent cryptographic applications for which the requirements, the context of use and the security properties can vary. It is therefore important, in the perspective of integrating QKD in security infrastructures, to analyze how QKD can be combined with other cryptographic primitives. The purpose of this survey article, which is mostly centered on European research results, is to contribute to such an analysis. We first review and compare the properties of the existing key establishment techniques, QKD being one of them. We then study more specifically two generic scenarios related to the practical use of QKD in cryptographic infrastructures: 1) using QKD as a key renewal technique for a symmetric cipher over a point-to-point link; 2) using QKD in a network containing many users with the objective of offering any-to-any key establishment service. We discuss the constraints as well as the potential interest of using QKD in these contexts. We finally give an overview of challenges relative to the development of QKD technology that also constitute potential avenues for cryptographic research.Comment: Revised version of the SECOQC White Paper. Published in the special issue on QKD of TCS, Theoretical Computer Science (2014), pp. 62-8

In the Battle for Reality: Social Documentaries in the U.S.

Provides an overview of documentaries that address social justice and democracy issues, and includes case studies of successful strategic uses of social documentaries

Social Justice Documentary: Designing for Impact

Explores current methodologies for assessing social issue documentary films by combining strategic design and evaluation of multiplatform outreach and impact, including documentaries' role in network- and field-building. Includes six case studies

Promoting Democracy through Civil Society: How to Step up the EU’s Policy towards the Eastern Neighbourhood. CEPS Working Documents No. 237, 1 February 2006

The European Union has successfully supported democratisation in its new Eastern member states and candidate countries. Now it needs to become more engaged in those post-communist countries where democratisation is incomplete or stalled. This study argues that civil society should be a more important priority of democracy promotion in the EU’s Eastern neighbourhood and calls for a strategic and differentiated approach designed according to the stage of democratisation in the target country. The paper focuses on three countries that represent three types of cases in the eastern neighbourhood: Ukraine, which has become a ‘re-transition’ country after the Orange Revolution; Moldova, where we can observe a prolonged transition; and Belarus, an outright dictatorship. One of the well-known obstacles to enhancing the EU’s support to civil society in these countries is posed by the bureaucratic procedures of aid programmes. However, even if the rules were substantially reformed, it would still be difficult for the European Commission to work extensively with NGOs in foreign countries for political as well as institutional reasons. Hence, the EU should create new mechanisms of democracy assistance. The German and US foundations set up specifically for this purpose have proved to be a model with many advantages; similar European foundation(s) could be an invaluable tool for supporting pro-democratic forces in authoritarian countries in particular. The paper also examines two other exemplary models for the European neighbourhood policy: the Swedish practice to channel support through domestic NGOs, and the EU’s own policy, which has only been applied in candidate countries so far, to use local civil society development foundations

Guest Editorial: Nonlinear Optimization of Communication Systems

Linear programming and other classical optimization techniques have found important applications in communication systems for many decades. Recently, there has been a surge in research activities that utilize the latest developments in nonlinear optimization to tackle a much wider scope of work in the analysis and design of communication systems. These activities involve every “layer” of the protocol stack and the principles of layered network architecture itself, and have made intellectual and practical impacts significantly beyond the established frameworks of optimization of communication systems in the early 1990s. These recent results are driven by new demands in the areas of communications and networking, as well as new tools emerging from optimization theory. Such tools include the powerful theories and highly efficient computational algorithms for nonlinear convex optimization, together with global solution methods and relaxation techniques for nonconvex optimization

Principles of Physical Layer Security in Multiuser Wireless Networks: A Survey

This paper provides a comprehensive review of the domain of physical layer security in multiuser wireless networks. The essential premise of physical-layer security is to enable the exchange of confidential messages over a wireless medium in the presence of unauthorized eavesdroppers without relying on higher-layer encryption. This can be achieved primarily in two ways: without the need for a secret key by intelligently designing transmit coding strategies, or by exploiting the wireless communication medium to develop secret keys over public channels. The survey begins with an overview of the foundations dating back to the pioneering work of Shannon and Wyner on information-theoretic security. We then describe the evolution of secure transmission strategies from point-to-point channels to multiple-antenna systems, followed by generalizations to multiuser broadcast, multiple-access, interference, and relay networks. Secret-key generation and establishment protocols based on physical layer mechanisms are subsequently covered. Approaches for secrecy based on channel coding design are then examined, along with a description of inter-disciplinary approaches based on game theory and stochastic geometry. The associated problem of physical-layer message authentication is also introduced briefly. The survey concludes with observations on potential research directions in this area.Comment: 23 pages, 10 figures, 303 refs. arXiv admin note: text overlap with arXiv:1303.1609 by other authors. IEEE Communications Surveys and Tutorials, 201