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Kosei SAKAMOTO Kazuhiko MINEMATSU Nao SHIBATA Maki SHIGERI Hiroyasu KUBO Yuki FUNABIKI Andrey BOGDANOV Sumio MORIOKA Takanori ISOBE
Tweakable block cipher (TBC) is an extension of conventional block cipher. We study how to build a TBC based on generalized Feistel structure (GFS), a classical block cipher construction. While known dedicated TBC proposals are based on substitution-permutation network (SPN), GFS has not been used for building TBC. In particular, we take 64-bit GFS block cipher TWINE and try to make it tweakable with a minimum change. To find a best one from a large number of candidates, we performed a comprehensive search with a help of mixed integer linear programming (MILP) solver. As a result, our proposal TWINE is quite efficient, has the same number of rounds as TWINE with extremely simple tweak schedule.
Chin-Pang LIU Alwyn SEEDS Jagvinder S. CHADHA Paul N. STAVRINOU Gareth PARRY Mark WHITEHEAD Andrey Bogdanovich KRYSA John Stuart ROBERTS
We have designed and fabricated air-bridged modulators with bandwidths exceeding 10 GHz, the highest yet realised to date for InGaAsP/InGaAsP multiple-quantum-well (MQW) asymmetric Fabry-Perot modulators (AFPMs). Microwave modulation, measurements of intermodulation between the photodetected downlink and modulated uplink signals, and bi-directional broadband data over fibre transmission experiments have been performed to verify the potential of the AFPM as a single electrical/optical transceiver. We also report the first direct integration of this AFPM with a microstrip patch antenna and present results of a preliminary microwave signal transmission experiment over a distance of 1.4 m in free-space at 5.2 GHz with the integrated AFPM as a photodetector.