New Lightweight Crypto Algorithms for RFID

G. Leander, Chris­tof Paar, Dipl.-Kfm. Axel Poschmann, Kai Schramm

IEEE International Symposium on Circuits and Systems - ISCAS 2007, New Orleans, Louisana, USA, Mai 27-30, 2007.


We propose a new block cipher, DESL (DES Lightweight extension), which is strong, compact and ef?cient 1 Due to its low area . constraints DESL is especially suited for RFID (Radio Frequency Identi?cation) devices. DESL is based on the classical DES (Data Encryption Standard) design, however, unlike DES it uses a single S-box repeated eight times. This approach makes it possible to considerably decrease chip size requirements. The S-box has been highly optimized in such a way that DESL resists common attacks, i.e., linear and differential cryptanalysis, and the Davies-Murphy-attack. Therefore DESL achieves a security level which is appropriate for many applications. Furthermore, we propose a light-weight implementation of DESL which requires 45% less chip size and 86% less clock cycles than the best AES implementations with regard to RFID applications. Compared to the smallest DES implementation published, our DESL design requires 38% less transistors. Our 0.18µm DESL implementation requires a chip size of 7392 transistors (1848 gate equivalences) and is capable to encrypt a 64-bit plaintext in 144 clock cycles. When clocked at 100 kHz, it draws an average current of only 0.89µA. These hardware ?gures are in the range of the best eSTREAM streamcipher candidates, comprising DESL as a new alternative for ultra low-cost encryption.

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