This paper investigates the security of KCipher-2 against differential attacks. We utilize an MILP-based method to evaluate the minimum number of active S-boxes in each round. We try to construct an accurate model to describe the 8-bit truncated difference propagation through the modular addition operation and the linear transformation of KCipher-2, respectively, which were omitted or simplified in the previous evaluation by Preneel et al. In our constructed model, the difference characteristics neglected in Preneel et al.'s evaluation can be taken into account and all valid differential characteristics can be covered. As a result, we reveal that the minimal number of active S-boxes is 25 over 15 rounds in the related IV setting and it is 17 over 24 rounds in the related IV-key setting. Therefore, this paper shows for the first time that KCipher-2 is secure against the related IV differential attack.
Jin HOKI
University of Hyogo
Kosei SAKAMOTO
University of Hyogo
Fukang LIU
University of Hyogo
Kazuhiko MINEMATSU
NEC Corporation
Takanori ISOBE
University of Hyogo,National Institute of Information and Communications Technology
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Jin HOKI, Kosei SAKAMOTO, Fukang LIU, Kazuhiko MINEMATSU, Takanori ISOBE, "MILP-Aided Security Evaluation of Differential Attacks on KCipher-2" in IEICE TRANSACTIONS on Fundamentals,
vol. E104-A, no. 1, pp. 203-212, January 2021, doi: 10.1587/transfun.2020CIP0018.
Abstract: This paper investigates the security of KCipher-2 against differential attacks. We utilize an MILP-based method to evaluate the minimum number of active S-boxes in each round. We try to construct an accurate model to describe the 8-bit truncated difference propagation through the modular addition operation and the linear transformation of KCipher-2, respectively, which were omitted or simplified in the previous evaluation by Preneel et al. In our constructed model, the difference characteristics neglected in Preneel et al.'s evaluation can be taken into account and all valid differential characteristics can be covered. As a result, we reveal that the minimal number of active S-boxes is 25 over 15 rounds in the related IV setting and it is 17 over 24 rounds in the related IV-key setting. Therefore, this paper shows for the first time that KCipher-2 is secure against the related IV differential attack.
URL: https://global.ieice.org/en_transactions/fundamentals/10.1587/transfun.2020CIP0018/_p
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@ARTICLE{e104-a_1_203,
author={Jin HOKI, Kosei SAKAMOTO, Fukang LIU, Kazuhiko MINEMATSU, Takanori ISOBE, },
journal={IEICE TRANSACTIONS on Fundamentals},
title={MILP-Aided Security Evaluation of Differential Attacks on KCipher-2},
year={2021},
volume={E104-A},
number={1},
pages={203-212},
abstract={This paper investigates the security of KCipher-2 against differential attacks. We utilize an MILP-based method to evaluate the minimum number of active S-boxes in each round. We try to construct an accurate model to describe the 8-bit truncated difference propagation through the modular addition operation and the linear transformation of KCipher-2, respectively, which were omitted or simplified in the previous evaluation by Preneel et al. In our constructed model, the difference characteristics neglected in Preneel et al.'s evaluation can be taken into account and all valid differential characteristics can be covered. As a result, we reveal that the minimal number of active S-boxes is 25 over 15 rounds in the related IV setting and it is 17 over 24 rounds in the related IV-key setting. Therefore, this paper shows for the first time that KCipher-2 is secure against the related IV differential attack.},
keywords={},
doi={10.1587/transfun.2020CIP0018},
ISSN={1745-1337},
month={January},}
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TY - JOUR
TI - MILP-Aided Security Evaluation of Differential Attacks on KCipher-2
T2 - IEICE TRANSACTIONS on Fundamentals
SP - 203
EP - 212
AU - Jin HOKI
AU - Kosei SAKAMOTO
AU - Fukang LIU
AU - Kazuhiko MINEMATSU
AU - Takanori ISOBE
PY - 2021
DO - 10.1587/transfun.2020CIP0018
JO - IEICE TRANSACTIONS on Fundamentals
SN - 1745-1337
VL - E104-A
IS - 1
JA - IEICE TRANSACTIONS on Fundamentals
Y1 - January 2021
AB - This paper investigates the security of KCipher-2 against differential attacks. We utilize an MILP-based method to evaluate the minimum number of active S-boxes in each round. We try to construct an accurate model to describe the 8-bit truncated difference propagation through the modular addition operation and the linear transformation of KCipher-2, respectively, which were omitted or simplified in the previous evaluation by Preneel et al. In our constructed model, the difference characteristics neglected in Preneel et al.'s evaluation can be taken into account and all valid differential characteristics can be covered. As a result, we reveal that the minimal number of active S-boxes is 25 over 15 rounds in the related IV setting and it is 17 over 24 rounds in the related IV-key setting. Therefore, this paper shows for the first time that KCipher-2 is secure against the related IV differential attack.
ER -