attacks on authentication Forced delay adversary intercepts a message and relays it at some later point in time(note: not the same as replay) Chosen-text attack on challenge-response where an adversary chooses challenges in an attempt to extract the secret key9 attacks on authentication • Forced delay – adversary intercepts a message and relays it at some later point in time (note: not the same as replay) • Chosen-text – attack on challenge-response where an adversary chooses challenges in an attempt to extract the secret key