Authentication system and method for operating the same

A challenge string is sent from a server to an authentication card. The challenge string is encrypted using a private key on the authentication card. Then, the encrypted challenge string is sent as a response from the authentication card to the server. A unique identifier of the authentication card is correlated to a user record residing at the server to obtain an authentication certificate from within the user record. The authentication certificate includes a public key. The public key from the authentication certificate is used to decrypt the response at the server. A determination is then made as to whether the decrypted response matches the challenge string as originally sent from the server to the authentication card. If the decrypted response matches the original challenge string, the authentication is successful. Otherwise, the authentication fails.