Cryptanalytic Attacks on IDEA Block Cipher

International data encryption algorithm (IDEA) is a secret key or symmetric key block cipher. The purpose of IDEA was to replace data encryption standard (DES) cipher, which became practically insecure due to its small key size of 56 bits and increase in computational power of systems. IDEA cipher mainly to provide data confidentiality in variety of applications such as commercial and financial application e.g. pretty good privacy (PGP) protocol. Till 2015, no successful linear or algebraic weaknesses IDEA of have been reported. In this paper, author explained IDEA cipher, its application in PGP and did a systematic survey of various attacks attempted on IDEA cipher. The best cryptanalysis result which applied to all keys could break IDEA up to 6 rounds out of 8.5 rounds of the full IDEA cipher1. But the attack requires 264 known plaintexts and 2126.8 operations for reduced round version. This attack is practically not feasible due to above mention mammoth data and time requirements. So IDEA cipher is still completely secure for practical usage. PGP v2.0 uses IDEA cipher in place of BassOmatic which was found to be insecure for providing data confidentiality

A Star-based Independent Biclique Attack on Full Rounds SQUARE

SQUARE is an iterated block cipher proposed by Daemen et.al. in FSE1997. Inspired by Bogdanov et.al.’s recent works [12], we first present an improved biclique attack, i.e. stat-based independent biclique attack on full rounds SQUARE in this paper. We construct a one round stat-based independent biclique for the initial round, and utilize matching with precomputation techniques to recover the whole key from the remaining rounds. The computing complexity of our attack is about $2^(126.17)$ encryptions and required data can be reduced to a single plaintext-ciphertext pair. To be the best of our knowledge, our attack has an optimal computing complexity and data complexity of biclique attack on full rounds SQUARE

Biclique Cryptanalysis Of PRESENT, LED, And KLEIN

In this paper, we analyze the resistance of the lightweight ciphers PRESENT, LED, and KLEIN to biclique attacks. Primarily, we describe attacks on the full-round versions PRESENT-80, PRESENT-128, LED-64, LED-128, KLEIN-80, and KLEIN-96. Our attacks have time complexities of $2^{79.49}$, $2^{127.32}$, $2^{63.58}$, $2^{127.42}$, $2^{79.00}$, and $2^{95.18}$ encryptions, respectively. In addition, we consider attacks on round-reduced versions of PRESENT and LED, to show the security margin for which an adversary can obtain an advantage of at least a factor of two compared to exhaustive search

Two Kinds of Biclique Attacks on Lightweight Block Cipher PRINCE

Inspired by the paper [10], using better differential characteristics in the biclique construction, we give another balanced biclique attack on full rounds PRINCE with the lower complexity in this paper. Our balanced biclique attack has 2^62.67 computational complexity and 2^32 data complexity. Furthermore, we first illustrate a star-based biclique attack on full rounds PRINCE cipher in this paper. Our star-based biclique attack has computational complexity 2^63.02 and the required data can be reduced to only a single plaintext-ciphertext pair, this is the optimal data complexity among the existing results of full round attack on PRINCE

SoK: Security Evaluation of SBox-Based Block Ciphers

Cryptanalysis of block ciphers is an active and important research area with an extensive volume of literature. For this work, we focus on SBox-based ciphers, as they are widely used and cover a large class of block ciphers. While there have been prior works that have consolidated attacks on block ciphers, they usually focus on describing and listing the attacks. Moreover, the methods for evaluating a cipher\u27s security are often ad hoc, differing from cipher to cipher, as attacks and evaluation techniques are developed along the way. As such, we aim to organise the attack literature, as well as the work on security evaluation. In this work, we present a systematization of cryptanalysis of SBox-based block ciphers focusing on three main areas: (1) Evaluation of block ciphers against standard cryptanalytic attacks; (2) Organisation and relationships between various attacks; (3) Comparison of the evaluation and attacks on existing ciphers

Bicliques with Minimal Data and Time Complexity for AES (Extended Version)

Biclique cryptanalysis is a recent technique that has been successfully applied to AES resulting in key recovery faster than brute force. However, a major hurdle in carrying out biclique cryptanalysis on AES is that it requires very high data complexity. This naturally warrants questions over the practical feasibility of implementing biclique attack in the real world. In Crypto\u2713, Canteaut et al. proposed biclique attack where the data complexity of the attack was reduced to a single plaintext-ciphertext pair. However, no application of the same on AES was suggested. In this paper, we re-evaluate the security-bound of full round AES against biclique attack. Under some reasonable restrictions, we exhaustively analyze the most promising class of biclique cryptanalysis as applied to AES through a computer-assisted search and find optimal attacks towards lowest computational and data complexities: - Among attacks with the minimal data complexity of the unicity distance, the ones with computational complexity 2^126.67 (for AES-128), 2^190.9 (for AES-192) and 2^255 (for AES-256) are the fastest. Each attack just requires 2 (for AES-128 and AES-192) or 3 (for AES-256) known plaintexts for success probability 1. We obtain these results using the improved biclique attack proposed in Crypto\u2713. - Among attacks with data complexity less than the full codebook, for AES-128, the ones of computational complexity 2^126.16 are fastest. Within these, the one with data complexity 2^64 requires the smallest amount of data. Thus, the original attack (with data complexity 2^88) did not have the optimal data complexity for AES-128. Similar findings are observed for AES-192 as well (data complexity 2^48 as against 2^80 in the original attack). For AES-256, we find an attack that has a lower computational complexity of 2^254.31 as compared to the original attack complexity of 2^254.42. - Among all attacks covered, the ones of computational complexity 2^125.56 (for AES-128), 2^189.51 (for AES-192) and 2^253.87 (for AES-256) are fastest, though requiring the full codebook. This can be considered as an indication of the limitations of the independent-biclique attack approach as applied to AES

Bicliques for permutations: collision and preimage attacks in stronger settings

We extend and improve biclique attacks, which were recently introduced for the cryptanalysis of block ciphers and hash functions. While previous attacks required a primitive to have a key or a message schedule, we show how to mount attacks on the primitives with these parameters fixed, i.e. on permutations. We introduce the concept of sliced bicliques, which is a translation of regular bicliques to the framework with permutations. The new framework allows to convert preimage attacks into collision attacks and derive the first collision attacks on the reduced SHA-3 finalist Skein in the hash function setting up to 11 rounds. We also demonstrate new preimage attacks on the reduced Skein and the output transformation of the reduced Grøstl. Finally, the sophisticated technique of message compensation gets a simple explanation with bicliques

Cryptanalysis of Block Ciphers with New Design Strategies

Block ciphers are among the mostly widely used symmetric-key cryptographic primitives, which are fundamental building blocks in cryptographic/security systems. Most of the public-key primitives are based on hard mathematical problems such as the integer factorization in the RSA algorithm and discrete logarithm problem in the DiffieHellman. Therefore, their security are mathematically proven. In contrast, symmetric-key primitives are usually not constructed based on well-defined hard mathematical problems. Hence, in order to get some assurance in their claimed security properties, they must be studied against different types of cryptanalytic techniques. Our research is dedicated to the cryptanalysis of block ciphers. In particular, throughout this thesis, we investigate the security of some block ciphers constructed with new design strategies. These new strategies include (i) employing simple round function, and modest key schedule, (ii) using another input called tweak rather than the usual two inputs of the block ciphers, the plaintext and the key, to instantiate different permutations for the same key. This type of block ciphers is called a tweakable block cipher, (iii) employing linear and non-linear components that are energy efficient to provide low energy consumption block ciphers, (iv) employing optimal diffusion linear transformation layer while following the AES-based construction to provide faster diffusion rate, and (v) using rather weak but larger S-boxes in addition to simple linear transformation layers to provide provable security of ARX-based block ciphers against single characteristic differential and linear cryptanalysis. The results presented in this thesis can be summarized as follows: Initially, we analyze the security of two lightweight block ciphers, namely, Khudra and Piccolo against Meet-in-the-Middle (MitM) attack based on the Demirci and Selcuk approach exploiting the simple design of the key schedule and round function. Next, we investigate the security of two tweakable block ciphers, namely, Kiasu-BC and SKINNY. According to the designers, the best attack on Kiasu-BC covers 7 rounds. However, we exploited the tweak to present 8-round attack using MitM with efficient enumeration cryptanalysis. Then, we improve the previous results of the impossible differential cryptanalysis on SKINNY exploiting the tweakey schedule and linear transformation layer. Afterwards, we study the security of new low energy consumption block cipher, namely, Midori128 where we present the longest impossible differential distinguishers that cover complete 7 rounds. Then, we utilized 4 of these distinguishers to launch key recovery attack against 11 rounds of Midori128 to improve the previous results on this cipher using the impossible differential cryptanalysis. Then, using the truncated differential cryptanalysis, we are able to attack 13 rounds of Midori128 utilizing a 10-round differential distinguisher. We also analyze Kuznyechik, the standard Russian federation block cipher, against MitM with efficient enumeration cryptanalysis where we improve the previous results on Kuznyechik, using MitM attack with efficient enumeration, by presenting 6-round attack. Unlike the previous attack, our attack exploits the exact values of the coefficients of the MDS transformation that is used in the cipher. Finally, we present key recovery attacks using the multidimensional zero-correlation cryptanalysis against SPARX-128, which follows the long trail design strategy, to provide provable security of ARX-based block ciphers against single characteristic differential and linear cryptanalysis