S-box is used in symmetric ciphers in cryptography. S-box = substitution box or lookup table [3][4]. You can see an example of Rijndael s-box in a python script

S-box is used in symmetric ciphers in cryptography. S-box = substitution box or lookup table [3][4]. You can see an example of Rijndael s-box in a python script here [1][2]. [1] https://github.com/kokke/tiny-AES-c/blob/f06ac37fc31dfdaca2e0d9bec83f90d5663c319b/aes.c#L79 https://github.com/kokke/tiny-AES-c/blob/f06ac37fc31dfdaca2e... [2] https://anh.cs.luc.edu/331/code/aes.py https://anh.cs.luc.edu/331/code/aes.py [3] https://en.wikipedia.org/wiki/S-box https://en.wikipedia.org/wiki/S-box [4] https://en.wikipedia.org/wiki/Rijndael_S-box https://en.wikipedia.org/wiki/Rijndael_S-box