If Alice has private key XA =3,what is Alice’s public key? b) If Bob has private key XB = 7 ,what is Bob’s public key? c) What is the shared secret key?

Alice and Bob use the ElGamal scheme with a common prime q= 131 and a primitive root a=6. Let Bob's public key be Yn=3. A. What is the ciphertext of M-9 if Alice chooses the random integer k=4? B. If Alice uses the same k to encrypt two messages M₁ and M₂ as (12, 65) and (12, 64), what is the relation between M₁ and M₂?

Alice and Bob agree to use the prime p = 1373 and the base g = 2 for communications using the Elgamal public key cryptosystem. Bob chooses b = 716 as his private key, so his public key is B ≡ 2716 ≡ 469 (mod 1373). Alice encrypts the message m = 583 using the random element k = 877. What is the ciphertext (c1, c2) that Alice sends to Bob?

Alice and Bob agree to use the prime p = 1373 and the base g = 2 for a Diffie–Hellman key exchange. Alice sends Bob the value A = 974. Bob asks your assistance, so you tell him to use the secret exponent b = 871. What value B should Bob send to Alice, and what is their secret shared value? Can you figure out Alice’s secret exponent?