as Wikipedia says: The affine cipher is a type of monoalphabetic substitution cipher, where each letter in an alphabet is mapped to its numeric equivalent, encrypted using a simple mathematical function, and converted back to a letter.
- look at the entire article from here: https://en.wikipedia.org/wiki/Affine_cipher
C = (a * P + b) mod 26
P = (a ^ -1 * (C - b)) mod 26
! Usage: python3 affinecipher.py <type> <string> <a> <b>
* type : {e: encryption, d: decryption}
* string : the text you want to encrypt or decrypt
* a : the first operand of the key
* b : the second operand of the key