Security evaluation on Simeck against zero-correlation linear cryptanalysis

SIMON and SPECK family ciphers have attracted the attention of cryptographers all over the world since proposed by NSA in June, 2013. At CHES 2015, Simeck, a new block cipher inspired from both SIMON and SPECK is proposed, which is more compact and efficient. However, the security evaluation on Simeck against zero correlation linear cryptanalysis seems missing from the specification. The main focus of this paper is to fill this gap and evaluate the security level on Simeck against zero correlation linear cryptanalysis. According to our study, 11/13/15 rounds zero correlation linear distinguishers on Simeck32/48/64 are proposed respectively, then zero correlation linear cryptanalysis on 20/24/27 rounds Simeck32/48/64 are firstly proposed. As far as we know, for Simeck32, our result is the best result to date.