Alamsyah
S-box is an integral part of the AES algorithm. The strength of the AES algorithm depends on the strength of the resulting S-box design. This study presents a simple S-box design by modifying the affine transformation. The S-box design in this paper uses the irreducible polynomial p(x) = x8 + x7 + x2 + x + 1. This irreducible polynomial decision is based on the results of previous research. The affine transformation modification is performed by taking 56 elements with a value of 0 from 64 elements of the affine matrix and using all elements with a value of 0 in an additional 8-bit constant. The test results of the proposed S-box design are nonlinearity, strict avalanche criterion, bit independence criterion-nonlinearity, and bit independence criterion-strict avalanche criterion are 112, 0.4995, 112, and 0.5017, respectively. These results indicate that the resulting S-box is stronger than in previous studies. © 2025 Author(s).
Computer Science Department, Universitas Negeri Semarang, Semarang, Indonesia
