CompTIA Security+ Exam Prep

Answer: B - A device that challenges at a random value called a nonce is an asynchronous token. The device generates a method to employ a challenge/response scheme to authenticate the user. The user enters this random value to the toke device, which encrypts it and returns a value the user uses as an on-time password. The user sends this value, along with a username, to the authentication server. If the authentication server can decrypt the value and it is the same challenge value sent earlier, the user is authenticated.