How is a challenge-response protocol utilized with token implementations?

A.
They are not; cryptography is used.

B.
An authentication service generates a challenge, and the smart token generates aresponse based on the challenge.

C.
The token challenges the user for a username and password.

D.
The token challenges the users password against a database of storedcredentials.

Explanation:
An asynchronous token device is based on challenge-responsemechanisms. The authentication service sends the user a challenge value and the userenters this into the token. The token encrypts or hashes this value and the useruses this as her one-time password.