Deoxys is a final-round candidate of the CAESAR competition. Deoxys is built upon an internal tweakable block cipher Deoxys-BC, where in addition to the plaintext and key, it takes an extra non-secret input called a tweak. This paper presents the first impossible differential cryptanalysis of Deoxys-BC-256 which is used in Deoxys as an internal tweakable block cipher. First, we find a 4.5-round...

In this paper, we improve the impossible differential attack on 20-round LBlock given in the design paper of the LBlock cipher. Using relations between the round keys we attack on 21-round and 22-round LBlock with a complexity of 2 and 2 encryptions respectively. We use the same 14-round impossible differential characteristic observed by the designers to attack on 21 rounds and another 14-round...

This paper studies the security of ARIA against impossible differential cryptanalysis. Firstly an algorithm is given to find many new 4-round impossible differentials of ARIA. Followed by such impossible differentials, we improve the previous impossible differential attack on 5/6-round ARIA. We also point out that the existence of such impossible differentials are due to the bad properties of t...

Since its introduction, impossible differential cryptanalysis has been applied to many ciphers. Besides the specific application of the technique in various instances, there are some very basic results which apply to generic structures of ciphers, e.g., the well known 5-round impossible differential of Feistel ciphers with bijective round functions. In this paper we present a new approach for t...

Impossible differential cryptanalysis is one of the cryptanalysis methods that are applicable to the new Advanced Encryption Standard (AES). In this paper, we present an introduction to the method by applying it on Mini-AES, the mini version of the AES published in Cryptologia recently.

Impossible differential is a useful method for cryptanalysis. SIMON is a light weight block cipher that has attracted lots of attention ever since its publication in 2013. In this paper we propose impossible differential attack on five versions of SIMON, using bit conditions to minimize key bits guessed. We calculate keybits and give the exact attack results.

In this paper, we analyze the security claims of Extended Generalized Feistel Networks (EGFNs) schemes proposed by Berger et al [1]. We provide impossible differentials for 10 rounds of EGFNs with 16 branches which add up one round to the claim of 9 rounds in the impossible differential trail. Therefore, impossible differential trail covers 10 rounds for the EGFNs scheme, which is the best resu...

We study applications of BV algorithm and present quantum versions of impossible differential cryptanalysis and truncated differential cryptanalysis based on it. Afterwards, we analyze their efficiencies and success probabilities rigorously. In traditional impossible differential attack or truncated differential attack, it is difficult to extend the differential path, which usually limits the n...

SKINNY is a new lightweight tweakable block cipher family proposed by Beierle et al. at CRYPTO 2016. SKINNY has 6 main variants where SKINNY-n-t is a block cipher that operates on n-bit blocks using t-bit tweakey (key and tweak) where n = 64 or 128 and t = n, 2n, or 3n. In this paper, we present impossible differential attacks against reduced-round versions of all the 6 members of the SKINNY fa...