Explain how one can decrypt the encrypted message using the encryption algorithm in part $($a$)?$ Write a program, in JavaScript, C$/$C$++$ or Python to take both the plaintext and the key as its input, then print out the plaintext. Test it using the results of the previous program. Add the screenshots of your program along the input and output and submit it as a PDF file. You should also submit the source code $[10$ marks$].$

Under what conditions $($specify two$)$ can a cipher be broken, meaning that an attacker can decipher the encrypted message without having the key? Support your reasoning with example$($s$)[6$ marks$].$

Identify THREE key factors for d