Answer:. Synchronous token
Explanation: Synchronous token is a device that is responsible behind the generation of the one-time passwords. These device work according to the time period and known to be time synchronized. Thus, it creates the OTP(one time password) for a limited period of time , usually for 60 seconds.They work according to the server along with the token. If there is the lapse of time of the OTP then it automatically gets out of work or marked as incorrect.
