About This Cipher
The Affine cipher is a type of encryption that uses a more complex mathematical formula (compared to Caesar cipher) to replace each letter in a message. This formula involves both addition and multiplication and allows for a wider range of keys to be used. The formula for the Affine cipher is usually given as: New letter = (a * Original letter + b) % 26 This formula involves multiplying the letter's position in the alphabet by a secret key 'a', adding another secret key 'b', and then "wrapping" the result around the alphabet by taking the remainder when divided by the number of letters in the alphabet 'm'. This remainder is used to determine the corresponding letter in the ciphertext alphabet.
About Cipher Key[s]
For the letters in the ciphertext to be unique, 'a' and 'm' must not share any common divisors, which is known as being coprime. In the case of the English alphabet, where 'm' is 26, 'a' must be an odd number and cannot be 13.