3. (20 marks) Cryptography (a) Compute ged(7,68) using the Euclidean algorithm. (b) For each of the following situations, describe the best available option for attempting to (i) You have 5000 characters of ciphertext, known to be encrypted using an affine ii) You have 10 characters of ciphertext, known to be encrypted using the Caesar ii) You have 500 characters of ciphertext, known to be encrypted using a one-time iv) You have 50 characters of ciphertext, known to be encrypted with the affine cipher (c) Using 3-5 sentences, explain the concept of a one-way function, and how they can be decode the ciphertext. Explain your chosen option, or why none exists. cipher cipher pad with an unpredictable and the first word of the plaintext is 'WEATHER key