• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.8
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• pp.1946-1963
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• 2012

Hummingbird is a lightweight encryption and message authentication primitive published in RISC'09 and WLC'10. In FSE'11, Markku-Juhani O.Saarinen presented a differential divide-and-conquer method which has complexity upper bounded by $2^{64}$ operations and requires processing of few megabytes of chosen messages under two related nonces (IVs). The improved version, Hummingbird-2, was presented in RFIDSec 2011. Based on the idea of differential collision, this paper discovers some weaknesses of the round function WD16. Combining with the simple key loading algorithm, a related-key chosen-IV attack which can recover the full secret key is proposed. Under 15 pairs of related keys, the 128 bit initial key can be recovered, requiring $2^{27}$ chosen IV and the computational complexity is $O(2^{27})$. In average, the attack needs several minutes to recover the full 128-bit secret key on a PC. The experimental result corroborates our attack. The result shows that the Hummingbird-2 cipher can't resist related key attack.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.5
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• pp.57-68
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• 2004

The rectangle attack and the related-key attack on block ciphers are well-known to be very powerful. In this paper we combine the rectangle attack with the related-key attack. Using this combined attack we can attack the SHACAL-1 cipher with 512-bit keys up to 59 out of its 80 rounds. Our 59-round attack requires a data complexity of $2^{149.72}$ chosen plaintexts and a time complexity of $2^{498.30}$ encryptions, which is faster than exhaustive search.

• Journal of Advanced Navigation Technology
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• v.13 no.6
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• pp.977-983
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• 2009

Recently, several DDP, DDO and COS-based block ciphers have been proposed for hardware implementations with low cost. However, most of them are vulnerable to related-keyt attacks. A 12-round block cipher SCOS-3 is desinged to eliminate the weakness of DDP, DDO and COS-based block ciphers. In this paper, we propose a related-key differential attack on an 11-round reduced SCOS-3. The attack on an 11-round reduced SCOS-3 requires $2^{58}$ related-key chosen plaintexts and $2^{117.54}$ 11-round reduced SCOS-3 encryptions. This work is the first known attack on SCOS-3. Therefore, SCOS-3 is still vulnerable to related-key attacks.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.14 no.3
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• pp.75-84
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• 2004

In this paper, we present a related key differential attack on Full-round GOST Firstly, we present a distinguishing attack on full rounds of GOST, which can distinguish it from random oracle with probability 1- 64$2^{64}$ using a related key differential characteristic. We will also show that H. Seki et al.'s idea can be applied to attack on 31 rounds of GOST combining our related key differential characteristic. Lastly, we propose a related key differential attack on full rounds of GOST. In this attack we can recover 12 bits of the master key with $2^{35}$ chosen plaintexts and $2^{36}$ encryption times for the 91.7% expectation of success rate.

• Journal of Platform Technology
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• v.11 no.1
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• pp.72-84
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• 2023

With the rise of the Internet of Things, the security of such lightweight computing environments has become a hot topic. Lightweight block ciphers that can provide efficient performance and security by having a relatively simpler structure and smaller key and block sizes are drawing attention. Due to these characteristics, they can become a target for new attack techniques. One of the new cryptanalytic attacks that have been attracting interest is Neural cryptanalysis, which is a cryptanalytic technique based on neural networks. It showed interesting results with better results than the conventional cryptanalysis method without a great amount of time and cryptographic knowledge. The first work that showed good results was carried out by Aron Gohr in CRYPTO'19, the attack was conducted on the lightweight block cipher SPECK-/32/64 and showed better results than conventional differential cryptanalysis. In this paper, we first apply the Differential Neural Distinguisher proposed by Aron Gohr to the block ciphers HIGHT and GOST to test the applicability of the attack to ciphers with different structures. The performance of the Differential Neural Distinguisher is then analyzed by replacing the neural network attack model with five different models (Multi-Layer Perceptron, AlexNet, ResNext, SE-ResNet, SE-ResNext). We then propose a Related-key Neural Distinguisher and apply it to the SPECK-/32/64, HIGHT, and GOST block ciphers. The proposed Related-key Neural Distinguisher was constructed using the relationship between keys, and this made it possible to distinguish more rounds than the differential distinguisher.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.9
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• pp.3266-3285
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• 2014

With limited computing and storage resources, many network applications of encryption algorithms require low power devices and fast computing components. CHESS-64 is designed by employing simple key scheduling and Data-Dependent operations (DDO) as main cryptographic components. Hardware performance for Field Programmable Gate Arrays (FPGA) and for Application Specific Integrated Circuits (ASIC) proves that CHESS-64 is a very flexible and powerful new cipher. In this paper, the security of CHESS-64 block cipher under related-key differential cryptanalysis is studied. Based on the differential properties of DDOs, we construct two types of related-key differential characteristics with one-bit difference in the master key. To recover 74 bits key, two key recovery algorithms are proposed based on the two types of related-key differential characteristics, and the corresponding data complexity is about $2^{42.9}$ chosen-plaintexts, computing complexity is about $2^{42.9}$ CHESS-64 encryptions, storage complexity is about $2^{26.6}$ bits of storage resources. To break the cipher, an exhaustive attack is implemented to recover the rest 54 bits key. These works demonstrate an effective and general way to attack DDO-based ciphers.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.4
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• pp.45-52
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• 2008

The slide resynchronization attack on Grain-v1 was proposed in [5]. Given the keystream sequence, this attack can generate the 1-bit shifted keystream sequence generated by Grain-v1. In this paper, extending the attack proposed in [5], we propose the key recovery attack on Grain-v1 using the related-key. Using the weakness of the initialization procedure of Grain-v1, this attack recover the master key with $2^{25.02}$ Ⅳs and $2^{56}$ time complexity. This attack is the first known key recovery attack on Grain-v1.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.24 no.3
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• pp.445-451
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• 2014

The related-key attack is regarded as one of the important cryptanalytic tools for the security evaluation of block ciphers. This is due to the fact that this attack can be effectively applied to schemes like block-cipher based hash functions whose block-cipher keys can be controlled as their messages. In this paper, we improve the related-key attack on lightweight block cipher PRINCE proposed in FSE 2013. Our improved related-key attack on PRINCE reduces data complexity from $2^{33}$ [4] to 2.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.15 no.3
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• pp.115-126
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• 2005

SHACAL-2 is a 256-bit block cipher with up to 512 bits of key length based on the hash function SHA-2. It was submitted to the the NESSIE project and was recommended as one of the NESSIE selections. In this paper, we present two types of related-key attacks called the related-key differential-(non)linear and the related-key rectangle attacks, and we discuss the security of SHACAL-2 against these two types of attacks. Using the related-key differential-nonlinear attack, we can break SHACAL-2 with 512-bit keys up to 35 out of its 64 rounds, and using the related-key rectangle attack, we can break SHACAL-2 with 512-bit keys up to 37 rounds.

• The KIPS Transactions:PartC
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• v.19C no.1
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• pp.55-62
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• 2012

KT-64 is a 64-bit block cipher which use CSPNs suitable for the efficient FPGA implementation. In this paper, we propose a related-key amplified boomerang attack on the full-round KT-64. The attack on the full-round KT-64 requires $2^{45.5}$ related-key chosen plaintexts and $2^{65.17}$ KT-64 encryptions. This work is the first known cryptanalytic result on KT-64.