### Abstract

The increment of opportunities for using machine learning (ML) technologies has brought a new threat to cryptosystems. As a remarkable example, the ML technologies have gradually been employed in the side-channel attack (SCA) to obtain sensitive information. In this paper, the authors focus on the structure of a masked S-Box in AES, which aims to equip the SCA resistance even for the attacks using the ML technologies. More precisely, this paper analyzes the mathematical structure of the inverse operation over F(2^{4})^{2} which is an isomorphic field for obtaining efficient arithmetic for the AES, so that all functions in the encryption scheme can handle masked data as it is. The mathematical structure is realized by introducing several mathematical tools such as the Gauss periods and the Itoh-Tsujii inversion algorithm, and as a result, we clarified the factors of the coefficients of A^{-1} for an element A F(2^{4})^{2}. It enables us to generate the corresponding element directly, which allows canceling the mask even after processing the SubBytes.

Original language | English |
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Title of host publication | Proceedings - 2019 7th International Symposium on Computing and Networking, CANDAR 2019 |

Publisher | Institute of Electrical and Electronics Engineers Inc. |

Pages | 157-163 |

Number of pages | 7 |

ISBN (Electronic) | 9781728147253 |

DOIs | |

Publication status | Published - Nov 2019 |

Event | 7th International Symposium on Computing and Networking, CANDAR 2019 - Nagasaki, Japan Duration: Nov 26 2019 → Nov 29 2019 |

### Publication series

Name | Proceedings - 2019 7th International Symposium on Computing and Networking, CANDAR 2019 |
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### Conference

Conference | 7th International Symposium on Computing and Networking, CANDAR 2019 |
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Country | Japan |

City | Nagasaki |

Period | 11/26/19 → 11/29/19 |

### Keywords

- AES
- Gauss periods
- Itoh Tsujii inversion algorithm
- isomorphic field F(2)
- masked S Box

### ASJC Scopus subject areas

- Computer Science Applications
- Computer Networks and Communications
- Hardware and Architecture
- Signal Processing

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## Cite this

*Proceedings - 2019 7th International Symposium on Computing and Networking, CANDAR 2019*(pp. 157-163). [8958480] (Proceedings - 2019 7th International Symposium on Computing and Networking, CANDAR 2019). Institute of Electrical and Electronics Engineers Inc.. https://doi.org/10.1109/CANDAR.2019.00027