Related-Key Impossible-Differential Attack on Reduced-Round Skinny
At CRYPTO’16, Beierle et al. presented SKINNY, a family of lightweight tweakable block ciphers intended to compete with the NSA designs SIMON and SPECK. SKINNY can be implemented efficiently in both soft- and hardware and supports block sizes of 64 and 128 bits as well as tweakey sizes of 64, 128, 192 and 128, 256, 384 bits respectively. This paper presents a related-tweakey impossible-differential attack on up to 23 (out of 36) rounds of SKINNY-64/128 for different tweak sizes. All our attacks can be trivially extended to SKINNY-128/128.
KeywordsSymmetric Cryptography Cryptanalysis Tweakable block cipher Impossible differential Lightweight cryptography
This work was initiated during the group sessions of the 6th Asian Workshop on Symmetric Cryptography (ASK 2016) held in Nagoya, Japan. Ralph Ankele is supported by the European Union’s Horizon 2020 research and innovation programme under grant agreement No. H2020-MSCA-ITN-2014-643161 ECRYPT-NET. Gaoli Wang is supported by National Natural Science Foundation of China (Grant Nos. 61572125, 61373142), Shanghai High-Tech Field Project (Grant No. 16511101400). Siang Meng Sim is supported by the Singapore National Research Foundation Fellowship 2012 (NRF-NRFF2012-06). This work has been supported in part by the Austrian Science Fund (project P26494-N15).
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