In a secure pattern matching scheme, a client learns only the locations where his private pattern matches a server’s private text, while server learns nothing. In this article, we propose a secure pattern matching protocol for the semi-honest setting which is then enhanced to guarantee full simulation-based security in the presence of malicious parties. The proposed protocol supports exact pattern matching, approximate pattern matching and pattern matching with wildcards. It is analytically shown that the proposed protocol is considerably more efficient in the approximate matching with at most$k$permitted mismatches while it has the same speed in the exact matching case comparing with the recent work in the literature. The achievements are also experimentally evaluated on a case of secure Desoxyribo-Nucleic Acid (DNA) search over the NCBI dataset of the United States national library of medicine. The results show efficiency of the proposed protocol and particularly confirm low computation overhead for the client.

SQUARE, an eight‐round substitution‐permutation block cipher, is considered as a predecessor of the advanced encryption standard (AES). Recently, the concept of biclique‐based key recovery of block ciphers was introduced and applied to full‐round versions of three variants of AES. In this paper, this technique is applied to analyse the block cipher SQUARE. First, a biclique for three rounds of SQUARE using independent related‐key differentials has been found. Then, an attack on this cipher is presented, with a data complexity of about 2 48 chosen plaintexts and a time complexity of about 2 125.7 encryptions. The attack is the first successful attack on full‐round SQUARE in the single‐key scenario.

Camellia, a 128-bit block cipher that has been accepted by ISO/IEC as an international standard, is increasingly being used in many cryptographic applications. In this study, the authors present a new impossible differential attack on a reduced version of Camellia-256 without FL/FL−1 functions and whitening. First, the authors introduce a new extension of the hash table technique and then exploit it to attack 16 rounds of Camellia-256. When, in an impossible differential attack, the size of the target subkey space is large and the filtration, in the initial steps of the attack, is performed slowly, the extended hash table technique will be very useful. The proposed attack on Camellia-256 requires 2124.1 known plaintexts and has a running time equivalent to about 2249.3 encryptions. In terms of the number of attacked rounds, our result is the best published attack on Camellia-256.

One of the most important structures used in modern block ciphers is the substitution–permutation network (SPN) structure. Many block ciphers with this structure widely use Maximun Distance Separable (MDS) matrices over finite fields as their diffusion layers, for example, advanced encryption standard (AES) uses a 4×4 MDS matrix as the main part of its diffusion layer and the block cipher Khazad has an involutory 8×8 matrix. In this study, first a construction is proposed for a 4×4 linear diffusion layer that can intermix four words of arbitrary size with branch number 5. Then extend this idea for 8×8 diffusion layer using low-cost linear functions. In this construction, first, certain binary linear combinations of inputs are fed into two or three different invertible linear functions and then combined using XOR operation. In order to show the efficiency of the proposed diffusion layer, the authors exploit it in a nested SPN structure and compare its efficiency with some well-known diffusion layers such as the diffusion layer of Hierocrypt.