In one aspect, a first processing device, which may be an authentication token, establishes a shared key through a pairing protocol carried out between the first processing device and a second processing device. The pairing protocol also involves communication between the second processing device and an authentication server. As part of the pairing protocol, the first processing device sends identifying information to the second processing device, and the second processing device utilizes the identifying information to obtain the shared key from the authentication server. The first processing device encrypts authentication information utilizing the shared key, and transmits the encrypted authentication information from the first processing device to the second processing device. The second processing device utilizes the shared key to decrypt the encrypted authentication information.