Reel-2. À plat. En repli. Reel-3. Crypt time. 29 December 2009. GSM A5 Files Published on Cryptome 27 April 2000. Thanks to Adi Shamir. This paper was presented at the Fast Software Encryption Workshop 2000, April 10-12, 2000, New York City. It supercedes an earlier version, "Real Time Cryptanalysis of the Alleged A5/1 on a PC (preliminary draft)," by Alex Biryukov and Adi Shamir, dated December 9, 1999. Original 18-page paper: (Postscript, 297K) Zipped Postscript: (104K) Alex Biryukov * Adi Shamir ** David Wagner *** Abstract. 1 Introduction The over-the-air privacy of GSM telephone conversations is protected by the A5 stream cipher. In this paper we develop two new cryptanalytic attacks on A5/1, in which a single PC can extract the conversation key in real time from a small amount of generated output.
Table 1. Many of the ideas in these two new attacks are applicable to other stream ciphers as well, and define new quantifiable measures of security. 3 Previous attacks. Region of interests. Grid diffuse. Stream track. Process unity. Psycho detector. Most modern information travels long distances in the form of infrared laser light, but when that data reaches its destination it requires devices called photodetectors to translate the optical language of data transfer into the electronic language of computation.
This week, researchers from the Vienna University of Technology (VUT) managed to create a silicon chip with an integrated photodetector made of graphene. The wonder material that seems poised to revolutionize so many industries might just change the way we build computers and networks, too. There are two key advantages to using graphene in this case. The first is simple: speed. The second advantage to graphene is the incredibly small size at which it will perform this function. The team’s major hurdle wasn’t proving graphene’s amazing abilities in optoelectronics, but integrating those abilities into a chip itself; you can’t just swap in this new graphene photodetector and use it with any old processor.
eVa in tri-color. For a whole number of reasons, I am currently looking into the visualisation of large-scale graphs and ontologies and to that end, I have made some notes concerning tools and concepts which might be useful for others. Here they are: Visualisation by Node-Link and Tree jOWL: jQuery Plugin for the navigation and visualisation of OWL ontologies and RDFS documents. Visualisations mainly as trees, navigation bars. OntoViz: Plugin into Protege…at the moment supports Protege 3.4 and doesn’t seem to work with Protege 4. IsaViz: Much the same as OntoViz really. Last stable version 2004 and does not seem to see active development. NeOn Toolkit: The Neon toolkit also has some visualisation capability, but not independent of the editor.
OntoTrack: OntoTrack is a graphical OWL editor and as such has visualisation capabilities. Cone Trees: Cone trees are three-dimensional extensions of 2D tree structures and have been designed to allow for a greater amount odf information to be visualised and navigated. eVa's 5-eyes. A good example is a local area network (LAN): Any given node in the LAN has one or more physical links to other devices in the network; graphically mapping these links results in a geometric shape that can be used to describe the physical topology of the network.
Conversely, mapping the data flow between the components determines the logical topology of the network. Topology There are two basic categories of network topologies: Physical topologiesLogical topologies The shape of the cabling layout used to link devices is called the physical topology of the network. The logical topology in contrast, is the way that the signals act on the network media, or the way that the data passes through the network from one device to the next without regard to the physical interconnection of the devices. Diagram of different network topologies. The study of network topology recognizes eight basic topologies: Point-to-pointBusStarRing or circularMeshTreeHybridDaisy chain Point-to-point eVa's n-eyes. Un article de Wikipédia, l'encyclopédie libre. Projection stéréographique des parallèles (en rouge) des méridiens (en bleu) et des hyperméridiens (en vert) de l'hypersphère : ce sont les lignes sur lesquelles une seule des coordonnées hypersphériques varie (voir le texte).
À cause des propriétés conformes de la projection stéréographique, les courbes se coupent orthogonalement (aux points jaunes), comme en 4D. Ce sont toutes des cercles, avec la convention que celles qui passent par <0,0,0,1> sont de rayon infini (des droites). Définition[modifier | modifier le code] En coordonnées cartésiennes, une 3-sphère de centre (C0, C1, C2, C3) et de rayon r est l'ensemble de tous les points (x0, x1, x2, x3) de l'espace (à 4 dimensions) réel R4 tels que : La 3-sphère centrée à l'origine et de rayon 1 s'appelle la 3-sphère unité, et est généralement notée S3: Il est souvent commode d'identifier R4 avec l'espace à deux dimensions complexes (C2), ou avec l'ensemble des quaternions (H).
Ou : . . Et .