13 results sorted by ID
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A Linearisation Method for Identifying Dependencies in Differential Characteristics: Examining the Intersection of Deterministic Linear Relations and Nonlinear Constraints
Ling Sun
Attacks and cryptanalysis
The analytical perspective employed in the study classifies the theoretical research on dependencies in differential characteristics into two types. By categorising all dependence representations from the value restrictions and the theory of quasidifferential trails, we pinpoint a specific set of nonlinear constraints, which we term linearised nonlinear constraints. We aim to establish a method that utilises value restrictions to identify these constraints, as the current method based on...
Equivalence of Generalised Feistel Networks
Patrick Derbez, Marie Euler
Secret-key cryptography
This paper focuses on equivalences between Generalised Feistel Networks (GFN) of type-II. We introduce a new definition of equivalence which captures the concept that two GFNs are identical up to re-labelling of the inputs/outputs, and give a procedure to test this equivalence relation. Such two GFNs are therefore cryptographically equivalent for several classes of attacks. It induces a reduction of the space of possible GFNs: the set of the $(k!)^2$ possible even-odd GFNs with $2k$ branches...
Automated Meet-in-the-Middle Attack Goes to Feistel
Qingliang Hou, Xiaoyang Dong, Lingyue Qin, Guoyan Zhang, Xiaoyun Wang
Attacks and cryptanalysis
Feistel network and its generalizations (GFN) are another important building blocks for constructing hash functions, e.g., Simpira v2, Areion, and the ISO standard Lesamnta-LW. The Meet-in-the-Middle (MitM) is a general paradigm to build preimage and collision attacks on hash functions, which has been automated in several papers. However, those automatic tools mostly focus on the hash function with Substitution-Permutation network (SPN) as building blocks, and only one for Feistel network by...
Towards Minimizing Non-linearity in Type-II Generalized Feistel Networks
Yuqing Zhao, Chun Guo, Weijia Wang
Secret-key cryptography
Recent works have revisited blockcipher structures to achieve MPC- and ZKP-friendly designs. In particular, Albrecht et al. (EUROCRYPT 2015) first pioneered using a novel structure SP networks with partial non-linear layers (P-SPNs) and then (ESORICS 2019) repopularized using multi-line generalized Feistel networks (GFNs). In this paper, we persist in exploring symmetric cryptographic constructions that are conducive to the applications such as MPC. In order to study the minimization of...
New Algorithm for Exhausting Optimal Permutations for Generalized Feistel Networks
Stéphanie Delaune, Patrick Derbez, Arthur Gontier, Charles Prud'homme
Secret-key cryptography
The Feistel construction is one of the most studied ways of building block ciphers. Several generalizations were proposed in the literature, leading to the Generalized Feistel Network (GFN) construction, in which the round function operates on each pair of blocks in parallel until all branches are permuted. At FSE'10, Suzaki and Minematsu studied the diffusion of such construction, raising the question of how many rounds are required so that each block of the ciphertext depends on all blocks...
Integral Cryptanalysis of WARP based on Monomial Prediction
Hosein Hadipour, Maria Eichlseder
Attacks and cryptanalysis
WARP is a 128-bit block cipher published by Banik et al. at SAC 2020 as a lightweight alternative to AES. It is based on a generalized Feistel network and achieves the smallest area footprint among 128-bit block ciphers in many settings. Previous analysis results include integral key-recovery attacks on 21 out of 41 rounds.
In this paper, we propose integral key-recovery attacks on up to 32 rounds by improving both the integral distinguisher and the key-recovery approach substantially....
Differential Cryptanalysis of WARP
Je Sen Teh, Alex Biryukov
Secret-key cryptography
WARP is an energy-efficient lightweight block cipher that is currently the smallest 128-bit block cipher in terms of hardware. It was proposed by Banik et al. in SAC 2020 as a lightweight replacement for AES-128 without changing the mode of operation. This paper proposes key-recovery attacks on WARP based on differential cryptanalysis in single and related-key settings. We searched for differential trails for up to 20 rounds of WARP, with the first 19 having optimal differential...
MILP Based Differential Attack on Round Reduced WARP
Manoj Kumar, Tarun Yadav
Secret-key cryptography
WARP is proposed by S. Banik et al. in SAC 2020. It is a 128-bit lightweight block cipher with 128-bit key. WARP is based on the
32-nibble type-2 Generalised Feistel Network (GFN) structure. It uses a permutation over nibbles which is designed to optimize the security and efficiency. The designers have provided a lower bound for the number of differentially active S-boxes but the detailed differential characteristics are not provided. In this paper, we discuss the MILP based search technique...
WARP : Revisiting GFN for Lightweight 128-bit Block Cipher
Subhadeep Banik, Zhenzhen Bao, Takanori Isobe, Hiroyasu Kubo, Fukang Liu, Kazuhiko Minematsu, Kosei Sakamoto, Nao Shibata, Maki Shigeri
Secret-key cryptography
In this article, we present WARP, a lightweight 128-bit block cipher with a 128-bit key. It aims at small-footprint circuit in the field of 128-bit block ciphers, possibly for a unified encryption and decryption functionality. The overall structure of WARP is a variant of 32-nibble Type-2 Generalized Feistel Network (GFN), with a permutation over nibbles designed to optimize the security and efficiency. We conduct a thorough security analysis and report comprehensive hardware and software...
A New Algorithm to Find Monic Irreducible Polynomials over Extended Galois field GF prime p and extension q using Positional Arithmetic
Sankhanil Dey, Amlan Chakrabarti, Ranjan Ghosh
Foundations
Search for monic irreducible polynomials (IPs) over extended Galois field GF(p^q) for a large value of the prime moduli p and a large extension to the Galois Field q is a well needed solution in the field of cryptography. In this paper a new algorithm to obtain monic IPs over extended Galois field GF(p^q) for the large values of p and q is introduced. Here in this paper the positional arithmetic is used to multiply all possible two monic elemental polynomials (EPs) with their Galois field...
Collision Attack on 4-branch, Type-2 GFN based Hash Functions using Sliced Biclique Cryptanalysis Technique
Megha Agrawal, Donghoon Chang, Mohona Ghosh, Somitra Kumar Sanadhya
Secret-key cryptography
In this work, we apply the sliced biclique cryptanalysis
technique to show 8-round collision attack on a hash function H
based on 4-branch, Type-2 Generalized Feistel Network (Type-2 GFN).
This attack is generic and works on 4-branch, Type-2 GFN with any
parameters including the block size, type of round function, the number of S-boxes in each round and the number of SP layers inside the round function. We first construct a 8-round distinguisher on 4-branch, Type-2 GFN and then use this...
Improved Meet-in-the-Middle Distinguisher on Feistel Schemes
Li Lin, Wenling Wu
Improved meet-in-the-middle cryptanalysis with efficient tabulation technique has been shown to be a very powerful form of cryptanalysis against SPN block ciphers. However, few literatures show the effectiveness of this cryptanalysis against Balanced-Feistel-Networks (BFN) and Generalized-Feistel-Networks (GFN) ciphers due to the stagger of affected trail and special truncated differential trail. In this paper, we describe a versatile and powerful algorithm for searching the best improved...
Analysis and Improvement of the Generic Higher-Order Masking Scheme of FSE 2012
Arnab Roy, Srinivas Vivek
Implementation
Masking is a well-known technique used to prevent block cipher implementations from side-channel attacks. Higher-order side channel attacks (e.g. higher-order DPA attack) on widely used block cipher like AES have motivated the design of efficient higher-order masking schemes. Indeed, it is known that as the masking order increases, the difficulty of side-channel attack increases exponentially. However, the main problem in higher-order masking is to design an efficient and secure technique...
The analytical perspective employed in the study classifies the theoretical research on dependencies in differential characteristics into two types. By categorising all dependence representations from the value restrictions and the theory of quasidifferential trails, we pinpoint a specific set of nonlinear constraints, which we term linearised nonlinear constraints. We aim to establish a method that utilises value restrictions to identify these constraints, as the current method based on...
This paper focuses on equivalences between Generalised Feistel Networks (GFN) of type-II. We introduce a new definition of equivalence which captures the concept that two GFNs are identical up to re-labelling of the inputs/outputs, and give a procedure to test this equivalence relation. Such two GFNs are therefore cryptographically equivalent for several classes of attacks. It induces a reduction of the space of possible GFNs: the set of the $(k!)^2$ possible even-odd GFNs with $2k$ branches...
Feistel network and its generalizations (GFN) are another important building blocks for constructing hash functions, e.g., Simpira v2, Areion, and the ISO standard Lesamnta-LW. The Meet-in-the-Middle (MitM) is a general paradigm to build preimage and collision attacks on hash functions, which has been automated in several papers. However, those automatic tools mostly focus on the hash function with Substitution-Permutation network (SPN) as building blocks, and only one for Feistel network by...
Recent works have revisited blockcipher structures to achieve MPC- and ZKP-friendly designs. In particular, Albrecht et al. (EUROCRYPT 2015) first pioneered using a novel structure SP networks with partial non-linear layers (P-SPNs) and then (ESORICS 2019) repopularized using multi-line generalized Feistel networks (GFNs). In this paper, we persist in exploring symmetric cryptographic constructions that are conducive to the applications such as MPC. In order to study the minimization of...
The Feistel construction is one of the most studied ways of building block ciphers. Several generalizations were proposed in the literature, leading to the Generalized Feistel Network (GFN) construction, in which the round function operates on each pair of blocks in parallel until all branches are permuted. At FSE'10, Suzaki and Minematsu studied the diffusion of such construction, raising the question of how many rounds are required so that each block of the ciphertext depends on all blocks...
WARP is a 128-bit block cipher published by Banik et al. at SAC 2020 as a lightweight alternative to AES. It is based on a generalized Feistel network and achieves the smallest area footprint among 128-bit block ciphers in many settings. Previous analysis results include integral key-recovery attacks on 21 out of 41 rounds. In this paper, we propose integral key-recovery attacks on up to 32 rounds by improving both the integral distinguisher and the key-recovery approach substantially....
WARP is an energy-efficient lightweight block cipher that is currently the smallest 128-bit block cipher in terms of hardware. It was proposed by Banik et al. in SAC 2020 as a lightweight replacement for AES-128 without changing the mode of operation. This paper proposes key-recovery attacks on WARP based on differential cryptanalysis in single and related-key settings. We searched for differential trails for up to 20 rounds of WARP, with the first 19 having optimal differential...
WARP is proposed by S. Banik et al. in SAC 2020. It is a 128-bit lightweight block cipher with 128-bit key. WARP is based on the 32-nibble type-2 Generalised Feistel Network (GFN) structure. It uses a permutation over nibbles which is designed to optimize the security and efficiency. The designers have provided a lower bound for the number of differentially active S-boxes but the detailed differential characteristics are not provided. In this paper, we discuss the MILP based search technique...
In this article, we present WARP, a lightweight 128-bit block cipher with a 128-bit key. It aims at small-footprint circuit in the field of 128-bit block ciphers, possibly for a unified encryption and decryption functionality. The overall structure of WARP is a variant of 32-nibble Type-2 Generalized Feistel Network (GFN), with a permutation over nibbles designed to optimize the security and efficiency. We conduct a thorough security analysis and report comprehensive hardware and software...
Search for monic irreducible polynomials (IPs) over extended Galois field GF(p^q) for a large value of the prime moduli p and a large extension to the Galois Field q is a well needed solution in the field of cryptography. In this paper a new algorithm to obtain monic IPs over extended Galois field GF(p^q) for the large values of p and q is introduced. Here in this paper the positional arithmetic is used to multiply all possible two monic elemental polynomials (EPs) with their Galois field...
In this work, we apply the sliced biclique cryptanalysis technique to show 8-round collision attack on a hash function H based on 4-branch, Type-2 Generalized Feistel Network (Type-2 GFN). This attack is generic and works on 4-branch, Type-2 GFN with any parameters including the block size, type of round function, the number of S-boxes in each round and the number of SP layers inside the round function. We first construct a 8-round distinguisher on 4-branch, Type-2 GFN and then use this...
Improved meet-in-the-middle cryptanalysis with efficient tabulation technique has been shown to be a very powerful form of cryptanalysis against SPN block ciphers. However, few literatures show the effectiveness of this cryptanalysis against Balanced-Feistel-Networks (BFN) and Generalized-Feistel-Networks (GFN) ciphers due to the stagger of affected trail and special truncated differential trail. In this paper, we describe a versatile and powerful algorithm for searching the best improved...
Masking is a well-known technique used to prevent block cipher implementations from side-channel attacks. Higher-order side channel attacks (e.g. higher-order DPA attack) on widely used block cipher like AES have motivated the design of efficient higher-order masking schemes. Indeed, it is known that as the masking order increases, the difficulty of side-channel attack increases exponentially. However, the main problem in higher-order masking is to design an efficient and secure technique...