Assume Bob send an Elgamal encrypted message to Alice. Wrongly, bob uses the same parameter ifor all messages. Moreover we know that each of Bob's clear text start with the number x1 = 21 (Bob's ID). We now obtain the following ciphertext (ke,1=6,y1=17) , (ke,2=6,y2=25). The Elgamal parameters are p=31, α = 3, β = 18. Determine the second plaintext x2