28,976 research outputs found
Lightweight Security for Network Coding
Under the emerging network coding paradigm, intermediate nodes in the network
are allowed not only to store and forward packets but also to process and mix
different data flows. We propose a low-complexity cryptographic scheme that
exploits the inherent security provided by random linear network coding and
offers the advantage of reduced overhead in comparison to traditional
end-to-end encryption of the entire data. Confidentiality is achieved by
protecting (or "locking") the source coefficients required to decode the
encoded data, without preventing intermediate nodes from running their standard
network coding operations. Our scheme can be easily combined with existing
techniques that counter active attacks.Comment: Proc. of the IEEE International Conference on Communications (ICC
2008), Beijing, China, May 200
TASI lectures on AdS/CFT
We introduce the AdS/CFT correspondence as a natural extension of QFT in a
fixed AdS background. We start by reviewing some general concepts of CFT,
including the embedding space formalism. We then consider QFT in a fixed AdS
background and show that one can define boundary operators that enjoy very
similar properties as in a CFT, except for the lack of a stress tensor.
Including a dynamical metric in AdS generates a boundary stress tensor and
completes the CFT axioms. We also discuss some applications of the bulk
geometric intuition to strongly coupled QFT. Finally, we end with a review of
the main properties of Mellin amplitudes for CFT correlation functions and
their uses in the context of AdS/CFT.Comment: 63 pages, 7 figure
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