Andrey Bogdanov Lars R. Knudsen Gregor Leander Christof Paar Axel Poschmann Matthew J. B. Robshaw Yannick Seurin C. Vikkelsoe PRESENT: An Ultra-Lightweight Block Cipher. 450-466 2007 conf/ches/2007 CHES http://dx.doi.org/10.1007/978-3-540-74735-2_31 db/conf/ches/ches2007.html#BogdanovKLPPRSV07