A general scheme for information interception in the ping pong protocol

The existence of an undetectable eavesdropping of dense coded information has been already demonstrated by Pavi\v{c}i\'c for the quantum direct communication based on the ping-pong paradigm. However, a) the explicit scheme of the circuit is only given and no design rules are provided, b) the existence of losses is implicitly assumed, c) the attack has been formulated against qubit based protocol only and it is not clear whether it can be adapted to higher dimensional systems. These deficiencies are removed in the presented contribution. A new generic eavesdropping scheme built on a firm theoretical background is proposed. In contrast to the previous approach, it does not refer to the properties of the vacuum state, so it is fully consistent with the absence of losses assumption. Moreover, the scheme applies to the communication paradigm based on signal particles of any dimensionality. It is also shown that some well known attacks are special cases of the proposed scheme.Comment: 10 pages, 4 figure

Quantum Secure Telecommunication Systems

This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing

Finite key size analysis of two-way quantum cryptography

Quantum cryptographic protocols solve the longstanding problem of distributing a shared secret string to two distant users by typically making use of one-way quantum channel. However, alternative protocols exploiting two-way quantum channel have been proposed for the same goal and with potential advantages. Here we overview a security proof for two-way quantum key distribution protocols, against the most general eavesdropping attack, that utilize an entropic uncertainty relation. Then, by resorting to the `smooth' version of involved entropies, we extend such a proof to the case of finite key size. The results will be compared to those available for one-way protocols showing some advantages

Telecommunications Networks

This book guides readers through the basics of rapidly emerging networks to more advanced concepts and future expectations of Telecommunications Networks. It identifies and examines the most pressing research issues in Telecommunications and it contains chapters written by leading researchers, academics and industry professionals. Telecommunications Networks - Current Status and Future Trends covers surveys of recent publications that investigate key areas of interest such as: IMS, eTOM, 3G/4G, optimization problems, modeling, simulation, quality of service, etc. This book, that is suitable for both PhD and master students, is organized into six sections: New Generation Networks, Quality of Services, Sensor Networks, Telecommunications, Traffic Engineering and Routing

Cultivating Extension Communities of Practice

This study empirically describes and analyzes the characteristics and functionality of the ―Communities of Practice (CoPs)‖ used within eXtension, a new initiative of the Cooperative Extension (CE) system. It also endeavors to lay the foundation for empirical analysis of CoP processes, which to date have been explained almost exclusively using qualitative case study methods. Land-grant universities were founded on the ideals that higher education should be accessible to all, that the university should teach liberal and practical subjects and should share the college\u27s knowledge with people throughout their states. eXtension is an educational partnership of more than 70 land-grant universities. Its reported purpose is to help Americans improve their lives with access to timely, objective, research-based information and educational opportunities accessed through http://www.extension.org . This Web resource is customized with links to state land-grant university CE Web sites. This mixed-method, action research project applied to the virtual environment describes the extent to which people who became part of an eXtension Communities of Practice (XCoPs) reported that they engaged in purposeful cycles of continuous inquiry in dialog, decision, action, and evaluation (DDAE) and the attainment of eXtension‘s goals. An Internet survey obtained descriptive data of members‘ participation within the eight pioneer XCoPs to assess the extent to which each XCoP engaged in the DDAE cycles of inquiry. Analysis of the survey data resulted in the categorization of low-, medium-, and high-level functioning XCoPs. Members of three pioneer XCoPs representing each category (low, medium, high collaboration) participated in online interviews that revealed how CE‘s reward structure, XCoP membership composition, and leader/member skill sets impact XCoP performance in meeting eXtension goals. Two sets of ―best practices‖ for eXtension initiative staff and XCoPs emerge from the discussion of triangulated data

Bell Nonlocality

Nonlocality was discovered by John Bell in 1964, in the context of the debates about quantum theory, but is a phenomenon that can be studied in its own right. Its observation proves that measurements are not revealing pre-determined values, falsifying the idea of “local hidden variables” suggested by Einstein and others. One is then forced to make some radical choice: either nature is intrinsically statistical and individual events are unspeakable, or our familiar space-time cannot be the setting for the whole of physics. As phenomena, nonlocality and its consequences will have to be predicted by any future theory, and may possibly play the role of foundational principles in these developments. But nonlocality has found a role in applied physics too: it can be used for “device-independent” certification of the correct functioning of random number generators and other devices. After a self-contained introduction to the topic, this monograph on nonlocality presents the main tools and results following a logical, rather than a chronological, order