Improved zero‐correlation and impossible differential cryptanalysis of reduced‐round SIMECK block cipher

Searching for impossible subspace trails and improved impossible differential characteristics for SIMON-like block ciphers

“…The longest impossible differentials include 11/12/13/16/19 rounds for SIMON32/48/64/96/128, respectively; and 11/13/15 for SIMECK32/48/64, respectively. While in Sadeghi and Bagheri (2018) gave 15-round and 17-round impossible differential characteristics for SIMECK48 and SIMECK64 respectively by manually finding the contradiction between two truncated differentials.…”

“…It is unadaptable for SIMON-like block ciphers searching impossible differentials by MILP until Wang et al provided an accurate MILP model for SIMON-like block ciphers in Wang et al (2018). They gave impossible differentials of 15-round for SIMECK48 and 17-round for SIMECK64 meeting the result in Sadeghi and Bagheri (2018), and two new 13-round for SIMON64. Leander et al proposed invariant subspace attack for PRINTcipher in Leander et al (2011).…”

“…For SIMECK32, our results cover the state-of-art (11-round) and shows much more trails as well. Sadeghi et al and Wang et al gave 15-round and 17-round impossible differential trails for SIMECK48 and SIMECK64 in Sadeghi and Bagheri (2018); Wang et al (2018), respectively. We will show in next section how to search these two trails and much more.…”

“…Two 13-round trails for SIMON64, 15-round trails for SIMECK48 and 17-round trails for SIMECK64 do not meet the requirement of the miss-in-the-middle approach, so they cannot be given by our algorithm in last section. In Sadeghi and Bagheri (2018), impossible differential trails for SIMECK48 and SIMECK64 are manually deduced, and this procedure tells us how the contradiction happens. However, random two properties will not lead to this contradiction.…”

Secure Data Encryption for Cloud-Based Human Care Services

“…They found that a 14-round related-key differential distinguisher for Simeck32/64 is the best known method, and they used the dependencies of bitwise AND operations. Sadeghi and Bagheri [10] proposed an improved miss-in-the-middle approach to find zero-correlation linear distinguishers and impossible differentials on Simeck48 and Simeck64. They attacked 15-round Simeck48 and 17-round Simeck64 using their proposed zero-correlation linear approximation method which relies on the duality of the zero-correlation and impossible differential, and they attacked 27-round Simeck48 and 31-round Simeck64 based on their proposed zero-correlation linear distinguishers.…”