Flaws in Differential Cryptanalysis of Reduced Round PRESENT

In this paper, we have presented flaws in differential cryptanalysis of reduced round variant of PRESENT given by M.Wang in [3] [4] for 80 bits key length and we have shown that it is not possible to recover 32 subkey bits by differential cryptanalysis of 16-round PRESENT as claimed in [3] [4].We have also shown that at the most 30 subkey bits can be recovered by the attack given in [4] after some modifications in the algorithm presented in [3][4]

Multiple Differential Cryptanalysis: Theory and Practice (Corrected)

Differential cryptanalysis is a well-known statistical attack on block ciphers. We present here a generalisation of this attack called multiple differential cryptanalysis. We study the data complexity, the time complexity and the success probability of such an attack and we experimentally validate our formulas on a reduced version of PRESENT. Finally, we propose a multiple differential cryptanalysis on 18-round PRESENT for both 80-bit and 128-bit master keys

Polytopic Cryptanalysis

Standard differential cryptanalysis uses statistical dependencies between the difference of two plaintexts and the difference of the respective two ciphertexts to attack a cipher. Here we introduce polytopic cryptanalysis which considers interdependencies between larger sets of texts as they traverse through the cipher. We prove that the methodology of standard differential cryptanalysis can unambiguously be extended and transferred to the polytopic case including impossible differentials. We show that impossible polytopic transitions have generic advantages over impossible differentials. To demonstrate the practical relevance of the generalization, we present new low-data attacks on round-reduced DES and AES using impossible polytopic transitions that are able to compete with existing attacks, partially outperforming these

Differential-ML Distinguisher: Machine Learning based Generic Extension for Differential Cryptanalysis

Differential cryptanalysis is an important technique to evaluate the security of block ciphers. There exists several generalisations of differential cryptanalysis and it is also used in combination with other cryptanalysis techniques to improve the attack complexity. In 2019, usefulness of machine learning in differential cryptanalysis is introduced by Gohr to attack the lightweight block cipher SPECK. In this paper, we present a framework to extend the classical differential distinguisher using machine learning (ML) based differential distinguisher. We propose a novel technique to construct differential-ML distinguisher for Feistel, SPN and ARX structure based block ciphers. We demonstrate our technique on lightweight block ciphers SPECK, SIMON & GIFT64 and construct differential-ML distinguishers for these ciphers. Data complexity for 9-round SPECK, 12-round SIMON & 8-round GIFT64 is reduced from 2^31 to 2^21, 2^34 to 2^22 and 2^28 to 2^22 respectively. The 12-round differential-ML distinguisher for SIMON is first distinguisher with data complexity less than 2^32

Cryptanalysis with Ternary Difference: Applied to Block Cipher PRESENT

Signed difference approach was first introduced by Wang for finding collision in MD5. In this paper we introduce ternary difference approach and present it in 3 symbols. To show its application we combine ternary difference approach with conventional differential cryptanalysis and apply that to cryptanalysis the reduced round PRESENT. We also use ant colony technique to obtain the best differential characteristic. To illustrate the privilege in the result of experiment, we calculate advantage of the attack

Differential Analysis of Round-Reduced AES Faulty Ciphertexts

International audienceThis paper describes new Round Reduction analysis attacks on an Advanced Encryption Standard (AES) implemen- tation by laser fault injection. The previous round reduction attacks require both of spatial and temporal accuracies in order to execute only one, two or nine rounds. We present new attacks by more flexible fault injection conditions. Our experiments are carried out on an 8-bit microcontroller which embeds a software AES with pre-calculated round keys. Faults are injected either into the round counter itself or into the reference of its total round number. The attacks may result to the use of a faulty round key at the last one or two executed rounds. The cryptanalysis of the obtained round-reduced faulty ciphertexts resorts to the differentiation techniques used by Differential Fault Analysis

A Security Analysis of IoT Encryption: Side-channel Cube Attack on Simeck32/64

Simeck, a lightweight block cipher has been proposed to be one of the encryption that can be employed in the Internet of Things (IoT) applications. Therefore, this paper presents the security of the Simeck32/64 block cipher against side-channel cube attack. We exhibit our attack against Simeck32/64 using the Hamming weight leakage assumption to extract linearly independent equations in key bits. We have been able to find 32 linearly independent equations in 32 key variables by only considering the second bit from the LSB of the Hamming weight leakage of the internal state on the fourth round of the cipher. This enables our attack to improve previous attacks on Simeck32/64 within side-channel attack model with better time and data complexity of 2^35 and 2^11.29 respectively.Comment: 12 pages, 6 figures, 4 tables, International Journal of Computer Networks & Communication