Affine Cipher Cryptanalysis Graded Programming Lab - Due Day Monday Oct 2

Option 1 (Full Credit 100 points) Write a program that accepts ciphertext only. The program finds the keys and decipher the message. To decipher the message use the program you wrote in Lab 1. Use letter frequency analysis and apply known plaintext attack after making assumption on possible plaintext letters.
Test your program on the following inputs. For the first input,write the detailed solution on the paper.
For this input you also have to write detailed solution and explain each step on the paper.
Ciphertext 1: EUJPE HUNKL NPOJK VNKSJ FKTBO LCHBU PBOMM NPKBK HPBOM BMAHU PNKLN POJKV Hint: Three most frequent letters in the ciphertext correspond to the plaintext letters O, S, and T not necessarily in that order
Ciphertext 2: SJEFWLUQGGWJUYQEUDFQJRUORFCAJOUNIHJOFFWJU
Ciphertext 3: VFFNJBSDRVYTXFVGJYTVMFSVJGTAIATHVWBYTVYOFVJBSZFJINJBSDJVYETABTWAFARIFAFVVJGV
Ciphertext 4: ACCKHUQFCOMPCIQVCMOBFJQVMZYPOLOHOBICFTCOHJTUHQZCMJUHC

Option 2 (maximal grade 85): If you have difficulties writing a general program, you can write a program that only finds keys using an algorithm that was explained in the lecture. The input for the program is four characters (two plaintext letters and two ciphertext letters). The output for the program: affine cipher keys A and B. You will use the above program to perform calculations.

Option 3 (maximal grade 75): Finding plaintext and keys for Ciphertexts 1, 2, 3, and 4 written above without any programming.