substitution box (S-Box)
Substitution box is an encryption method that works according to the substitution cipher. It uses a character list in which an entered character is replaced by another one. This list is also known as substitution box or S-box.
In the substitution box, matrices of data words with a keyword of the same length as the data word are combined in a logical operation to form a new data word. An XOR operation is usually used as the logical operation.
Depending on the method, the character lists are specified in the standard, as in the DES algorithm.