221). Unfortunately, she forgot the private key to decrypt 76 (the cipher text) to get the PIN code. She only remembers when generating the key, she chose p = 17. Please help her to find the PIN code.
Q2(1 point). You agreed to use a Caesar cipher with a key of k=3 with a friend.While sitting in a group, the friend hands you over a message that says "LORYHBRX". Decrypt the message?
Q3(1 point). Suppose you receive an encrypted message "XUWWLUD" and know that it is encrypted with the Caesar cipher, but you forget the key. How many decoding calculations do you need to find the original text?
Q4(1.5 point). Decrypt this message "12 34 18 48 16 10 18 2" using the
following paragraph as reference code book: "Once upon a time there was a piece of yellow wood. It was not an expensive piece of wood. Far from it. Just a common block of firewood, one of those thick, solid logs that are put on the fire
in winter to make cold rooms cozy, vivid and warm"?Q5(0.5 point). Euler totient function of n (we use the Greek symbol phi to denote Euler totient function) is the number of positive integers that are between 1 and n-1, inclusive, and are relatively prime to n. What is the Euler totient function of 605?
Q6(1.5 point). Using the same notations as in the lecture, e.g., p and q are the two primes and e and d are the public key and the private key, respectively, p = 5, q11, e 7. What is the value of phi(n) where phi(n) is the Euler Totient function of n and n is the modulus of RSA cipher?
Using the phi(n) that you found and the Extended Euclidean algorithm yields d = 23. What is the ciphertext C when encrypting M = 17?
Q7(0.5 point). Calculate the shared secret key using the Diffie-Hellman key exchange protocol with specific data. Given the following parameters:
Prime number p: 79
Primitive root g: 5
Alice's secret value (a): 11
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