on 01-06-2012
Arnaldo Gouveia, SQIG - IT
01/06/2012, 15:00
Room P4.35, Mathematics Building
In the current Quantum Key Distribution (QKD) roposals it is possible to generate a secret key and distribute it with the involved parties separated in physical terms. This possibility opens the possibility of structuring a a solution to the the classical cryptography problem of key distribution with reduced interaction among involved parties. Among other proposals to adress this issue is the Eckert 91 protocol wich will be in scope in this report. Proposed
in 1991 by A. Eckert it is an entanglement based protocol. The security assurance of entanglement based protocols is based on impossibility of an eavesdropper has to clone a message without estroying it. As such the receiver has the possibility to detect eavesdropping and this is a major advantage of this type of protocols. In the end the a security proof will be described.
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on 01-06-2012
Manuel Campagnolo, ISA - TU Lisbon / SQIG - IT
June 1, 2012, Friday, 16h15m.
Abstract: The functions of computable analysis are defined by enhancing normal Turing machines to deal with real number inputs. One can consider characterizations of these functions using function algebras, known as real recursive functions. Since there are numerous incompatible models of computation over the reals, it is interesting to find that the two very different models we consider can be set up to yield exactly the same functions. Bournez and Hainry used a function algebra to characterize computable analysis, restricted to the twice continuously differentiable functions with compact domains. Campagnolo and Ojakian found a different (and apparently more natural) function algebra that also yields computable analysis, with the same restriction. In this talk I will describe an improvement of earlier work, finding three function algebras characterizing computable analysis, removing the restriction to twice continuously differentiable functions and allowing unbounded domains. One of these function algebras is built upon the widely studied real primitive recursive functions. Furthermore, the proof uses the previously developed method of approximation, whose applicability is further evidenced by those results. This talk reports on joint work with Kerry Ojakian.
Room: 3.10, Mathematics
Support: SQIG/Instituto de Telecomunicações with support from FCT and FEDER namely by the FCT project PEst-OE/EEI/LA0008/2011.
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