The first project of the COMP543: Modern Cryptography, Koç University Fall 2022
Part I: Attacking a shift cipher
In this part, I attacked a shift cipher given the ciphertext using the frequency analysis method.
I found the key and the plaintext.
Part II: Attacking a vigenere cipher
In this part, I attacked a vigenere cipher given the ciphertext.
First, I found the key length using Kasiski's method. Then, I, again, used the frequency analysis method.
I found the key and the plaintext.