Multiplicative Cipher

Downward Arrow

Introduction

The multiplicative cipher is similar to additive cipher except the fact that the key bit is multiplied to the plain-text symbol during encryption.

Also, the cipher-text is multiplied by the multiplicative inverse of key for decryption to obtain back the plain-text. 

                    C = (M * k) mod n
                    M = (C * (k)power(-1)) mod n
                    M - Message, K - Key, n - number of alphabets, C - Cipher Text,

                    where,
                    (k)power(-1) -> multiplicative inverse of k (key)

                    The key space of multiplicative cipher is 12. Thus, it is also not very secure.

Implementation


Plaintext:

Key:

Ciphered Text:


Ciphered Text:

Key:

Plain Text: