Abstract: A dynamic command protection method includes generating salt data by a physically linked device after an authentication of the physically linked device is verified, transmitting the salt data from the physically linked device to a computer terminal, transmitting at least one command protected by the salt data during a first time interval from the computer terminal to the physically linked device, verifying the salt data if the at least one command is valid, executing at least one valid command after the salt data is successfully verified, and updating the salt data after the first time interval elapses. The salt data is bound to the physically linked device and is generated according to a time-varying value.