Exercise 2. Classic Ciphers [12 points] You know that your friend always uses one of the two following passwords: "abcd" or "kdmf". You get to see an encryption of your friend's password, can you find what was it if (WITHOUT assuming any type of brute-forcing, your attack should work by observation or pen and paper calculations.): (a.) The encryption was done using the Caesar's (or shift) cipher? (b.) The encryption was done using Vigener cipher with key length 2? (c.) The encryption was done using Vigener cipher with key length 3? d) The encrvption was done using Vigener cipher with key length 4