Why is the EKE-based Protocol 10-7 insecure? (Hint: someone impersonating Bob can do a dictionary attack, but show how.) How can you make it secure while still having Bob transmit g^b mod p unencrypted?

(*) Consider Protocol 10-8. How would Alice compute K? How would Bob compute K. Why is it insecure? (Hint: someone impersonating Bob can do a dictionary attack, but show how.)