Differential Fault Attack on SKINNY Block Cipher

SKINNY is a family of tweakable lightweight block ciphers, proposed in CRYPTO 2016. The proposal of SKINNY describes two block size variants of 64 and 128 bits as well as three options for tweakey. In this paper, we present differential fault analysis (DFA) of four SKINNY variants - SKINNY 64-64, SKINNY 128-128, SKINNY 64-128 and SKINNY 128-256. The attack model of tweakable block ciphers allow the access and full control of the tweak by the attacker. Respecting this attack model, we assume a fixed tweak for the attack window. With this assumption, extraction of the master key of SKINNY requires about 10 nibble fault injections on average for 64-bit versions of the cipher, whereas the 128-bit versions require roughly 21 byte fault injections. The attacks were validated through extensive simulation. To the best of authors' knowledge, this is the first DFA attack on SKINNY tweakable block cipher family and, in fact, any practical realization of tweakable block ciphers.