scholarly journals Towards Key-recovery-attack Friendly Distinguishers: Application to GIFT-128

2021 ◽  
pp. 156-184
Author(s):  
Rui Zong ◽  
Xiaoyang Dong ◽  
Huaifeng Chen ◽  
Yiyuan Luo ◽  
Si Wang ◽  
...  
Keyword(s):  
Block Cipher ◽  
Recovery Process ◽  
Low Complexity ◽  
Differential Cryptanalysis ◽  
Linear Cryptanalysis ◽  
Linear Hull ◽  
Differential Attack ◽  
Key Recovery ◽  
Key Recovery Attack

When analyzing a block cipher, the first step is to search for some valid distinguishers, for example, the differential trails in the differential cryptanalysis and the linear trails in the linear cryptanalysis. A distinguisher is advantageous if it can be utilized to attack more rounds and the amount of the involved key bits during the key-recovery process is small, as this leads to a long attack with a low complexity. In this article, we propose a two-step strategy to search for such advantageous distinguishers. This strategy is inspired by the intuition that if a differential is advantageous only when some properties are satisfied, then we can predefine some constraints describing these properties and search for the differentials in the small set.As applications, our strategy is used to analyze GIFT-128, which was proposed in CHES 2017. Based on some 20-round differentials, we give the first 27-round differential attack on GIFT-128, which covers one more round than the best previous result. Also, based on two 17-round linear trails, we give the first linear hull attack on GIFT-128, which covers 22 rounds. In addition, we also give some results on two GIFT-128 based AEADs GIFT-COFB and SUNDAE-GIFT.

scholarly journals Clustering Related-Tweak Characteristics: Application to MANTIS-6

2018 ◽  
pp. 111-132
Author(s):  
Maria Eichlseder ◽  
Daniel Kales
Keyword(s):  
Block Cipher ◽  
Differential Cryptanalysis ◽  
Differential Attack ◽  
Key Recovery ◽  
Popular Approach ◽  
Differential Characteristic ◽  
Clustering Approach ◽  
Tweakable Block Cipher ◽  
Key Recovery Attack ◽  
Truncated Differential

The TWEAKEY/STK construction is an increasingly popular approach for designing tweakable block ciphers that notably uses a linear tweakey schedule. Several recent attacks have analyzed the implications of this approach for differential cryptanalysis and other attacks that can take advantage of related tweakeys. We generalize the clustering approach of a recent differential attack on the tweakable block cipher MANTIS5 and describe a tool for efficiently finding and evaluating such clusters. More specifically, we consider the set of all differential characteristics compatible with a given truncated characteristic, tweak difference, and optional constraints for the differential. We refer to this set as a semi-truncated characteristic and estimate its probability by analyzing the distribution of compatible differences at each step. We apply this approach to find a semi-truncated differential characteristic for MANTIS6 with probability about 2−67.73 and derive a key-recovery attack with a complexity of about 255.09 chosen-plaintext queries and 255.52 computations. The data-time product is 2110.61 << 2126.

scholarly journals Cryptanalysis of Reduced round SKINNY Block Cipher

2018 ◽  
pp. 124-162 ◽  
Author(s):  
Sadegh Sadeghi ◽  
Tahereh Mohammadi ◽  
Nasour Bagheri
Keyword(s):  
Mixed Integer Linear Programming ◽  
Block Cipher ◽  
Mixed Integer ◽  
Differential Attack ◽  
Key Recovery ◽  
Zero Correlation ◽  
Impossible Differential ◽  
Key Recovery Attack ◽  
Correlation Attacks ◽  
Impossible Differential Cryptanalysis

SKINNY is a family of lightweight tweakable block ciphers designed to have the smallest hardware footprint. In this paper, we present zero-correlation linear approximations and the related-tweakey impossible differential characteristics for different versions of SKINNY .We utilize Mixed Integer Linear Programming (MILP) to search all zero-correlation linear distinguishers for all variants of SKINNY, where the longest distinguisher found reaches 10 rounds. Using a 9-round characteristic, we present 14 and 18-round zero correlation attacks on SKINNY-64-64 and SKINNY- 64-128, respectively. Also, for SKINNY-n-n and SKINNY-n-2n, we construct 13 and 15-round related-tweakey impossible differential characteristics, respectively. Utilizing these characteristics, we propose 23-round related-tweakey impossible differential cryptanalysis by applying the key recovery attack for SKINNY-n-2n and 19-round attack for SKINNY-n-n. To the best of our knowledge, the presented zero-correlation characteristics in this paper are the first attempt to investigate the security of SKINNY against this attack and the results on the related-tweakey impossible differential attack are the best reported ones.

scholarly journals New Linear Cryptanalysis of Chinese Commercial Block Cipher Standard SM4

2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Yu Liu ◽  
Huicong Liang ◽  
Wei Wang ◽  
Meiqin Wang
Keyword(s):  
Wireless Communication ◽  
Linear Approximation ◽  
Block Cipher ◽  
Linear Cryptanalysis ◽  
Key Recovery ◽  
Linear Approximations ◽  
Partial Linear ◽  
Key Recovery Attack ◽  
Better Than

SM4 is a Chinese commercial block cipher standard used for wireless communication in China. In this paper, we use the partial linear approximation table of S-box to search for three rounds of iterative linear approximations of SM4, based on which the linear approximation for 20-round SM4 has been constructed. However, the best previous identified linear approximation only covers 19 rounds. At the same time, a linear approximation for 19-round SM4 is obtained, which is better than the known results. Furthermore, we show the key recovery attack on 24-round SM4 which is the best attack according to the number of rounds.

scholarly journals Crypto-Archaeology: unearthing design methodology of DES s-boxes

2017 ◽  
Author(s):  
Sankhanil Dey ◽  
Ranjan Ghosh
Keyword(s):  
Boolean Function ◽  
Boolean Functions ◽  
Design Methodology ◽  
Block Cipher ◽  
Block Ciphers ◽  
Public Domain ◽  
Differential Cryptanalysis ◽  
Linear Cryptanalysis ◽  
Strict Avalanche Criterion ◽  
Independence Criterion

US defence sponsored the DES program in 1974 and released it in 1977. It remained as a well-known and well accepted block cipher until 1998. Thirty-two 4-bit DES S-Boxes are grouped in eight each with four and are put in public domain without any mention of their design methodology. S-Boxes, 4-bit, 8-bit or 32-bit, find a permanent seat in all future block ciphers. In this paper, while looking into the design methodology of DES S-Boxes, we find that S-Boxes have 128 balanced and non-linear Boolean Functions, of which 102 used once, while 13 used twice and 92 of 102 satisfy the Boolean Function-level Strict Avalanche Criterion. All the S-Boxes satisfy the Bit Independence Criterion. Their Differential Cryptanalysis exhibits better results than the Linear Cryptanalysis. However, no S-Boxes satisfy the S-Box-level SAC analyses. It seems that the designer emphasized satisfaction of Boolean-Function-level SAC and S-Box-level BIC and DC, not the S-Box-level LC and SAC.

scholarly journals Provable Security Against a Differential Attack

1994 ◽  
Vol 23 (473) ◽  
Author(s):  
Kaisa Nyberg ◽  
Lars Ramkilde Knudsen
Keyword(s):  
Upper Bound ◽  
Provable Security ◽  
Block Cipher ◽  
Differential Cryptanalysis ◽  
Font Size ◽  
Differential Attack ◽  
Round Function ◽  
Differential Attacks

The purpose of this paper is to show that there exist DES-like iterated ciphers, which are provably resistant against differential attacks. The main result on the security of a DES-like cipher with independent round keys is Theorem 1, which gives an upper bound to the probability of <em>s</em>-round differentials, as defined in <em>Markov Ciphers and Differential Cryptanalysis </em> by X. Lai et al. and this upper bound depends only on the round function of the iterated cipher. Moreover, it is shown that there exist functions such that the probabilities of differentials are less than or equal to 2<sup><span style="font-size: x-small;">3-n</span></sup>, where <em>n</em> is the length of the plaintext block. We also show a prototype of an iterated block cipher, which is compatible with DES and has proven security against differential attacks.

scholarly journals Boomeyong: Embedding Yoyo within Boomerang and its Applications to Key Recovery Attacks on AES and Pholkos

2021 ◽  
pp. 137-169
Author(s):  
Mostafizar Rahman ◽  
Dhiman Saha ◽  
Goutam Paul
Keyword(s):  
Time Complexity ◽  
Block Cipher ◽  
New Technique ◽  
Small Scale ◽  
Key Recovery ◽  
Boomerang Attack ◽  
Tweakable Block Cipher ◽  
Key Recovery Attack ◽  
Key Recovery Attacks

This work investigates a generic way of combining two very effective and well-studied cryptanalytic tools, proposed almost 18 years apart, namely the boomerang attack introduced by Wagner in FSE 1999 and the yoyo attack by Ronjom et al. in Asiacrypt 2017. In doing so, the s-box switch and ladder switch techniques are leveraged to embed a yoyo trail inside a boomerang trail. As an immediate application, a 6-round key recovery attack on AES-128 is mounted with time complexity of 278. A 10-round key recovery attack on recently introduced AES-based tweakable block cipher Pholkos is also furnished to demonstrate the applicability of the new technique on AES-like constructions. The results on AES are experimentally verified by applying and implementing them on a small scale variant of AES. We provide arguments that draw a relation between the proposed strategy with the retracing boomerang attack devised in Eurocrypt 2020. To the best of our knowledge, this is the first attempt to merge the yoyo and boomerang techniques to analyze SPN ciphers and warrants further attention as it has the potential of becoming an important cryptanalysis tool.

scholarly journals Cryptanalysis of Round-Reduced Fantomas, Robin and iSCREAM

Cryptography ◽  
2019 ◽  
Vol 3 (1) ◽  
pp. 4 ◽  
Author(s):  
Ashutosh Dwivedi ◽  
Shalini Dhar ◽  
Gautam Srivastava ◽  
Rajani Singh
Keyword(s):  
Side Channel ◽  
Linear Cryptanalysis ◽  
Key Recovery ◽  
Side Channel Analysis ◽  
Linear Characteristic ◽  
Random Behavior ◽  
Channel Analysis ◽  
Key Recovery Attack

In this work, we focus on LS-design ciphers Fantomas, Robin, and iSCREAM. LS-designs are a family of bitslice ciphers aimed at efficient masked implementations against side-channel analysis. We have analyzed Fantomas and Robin with a technique that previously has not been applied to both algorithms or linear cryptanalysis. The idea behind linear cryptanalysis is to build a linear characteristic that describes the relation between plaintext and ciphertext bits. Such a relationship should hold with probability 0.5 (bias is zero) for a secure cipher. Therefore, we try to find a linear characteristic between plaintext and ciphertext where bias is not equal to zero. This non-random behavior of cipher could be converted to some key-recovery attack. For Fantomas and Robin, we find 5 and 7-round linear characteristics. Using these characteristics, we attack both the ciphers with reduced rounds and recover the key for the same number of rounds. We also apply linear cryptanalysis to the famous CAESAR candidate iSCREAM and the closely related LS-design Robin. For iScream, we apply linear cryptanalysis to the round-reduced cipher and find a 7-round best linear characteristics. Based on those linear characteristics we extend the path in the related-key scenario for a higher number of rounds.

scholarly journals Automated Search Oriented to Key Recovery on Ciphers with Linear Key Schedule

2021 ◽  
pp. 249-291
Author(s):  
Lingyue Qin ◽  
Xiaoyang Dong ◽  
Xiaoyun Wang ◽  
Keting Jia ◽  
Yunwen Liu
Keyword(s):  
High Probability ◽  
Block Cipher ◽  
Secret Key ◽  
Key Recovery ◽  
Key Schedule ◽  
Before And After ◽  
Two Phases ◽  
Key Recovery Attack ◽  
Key Recovery Attacks ◽  
Automated Search

Automatic modelling to search distinguishers with high probability covering as many rounds as possible, such as MILP, SAT/SMT, CP models, has become a very popular cryptanalysis topic today. In those models, the optimizing objective is usually the probability or the number of rounds of the distinguishers. If we want to recover the secret key for a round-reduced block cipher, there are usually two phases, i.e., finding an efficient distinguisher and performing key-recovery attack by extending several rounds before and after the distinguisher. The total number of attacked rounds is not only related to the chosen distinguisher, but also to the extended rounds before and after the distinguisher. In this paper, we try to combine the two phases in a uniform automatic model.Concretely, we apply this idea to automate the related-key rectangle attacks on SKINNY and ForkSkinny. We propose some new distinguishers with advantage to perform key-recovery attacks. Our key-recovery attacks on a few versions of round-reduced SKINNY and ForkSkinny cover 1 to 2 more rounds than the best previous attacks.

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