| 摘要 |
An attendance device, comprises a counter arranged to generate a counter value representative of a time elapsed from registration of the attendance device with a server, a memory for storing an encryption key and a unique identifier associated with the attendance device, and processor adapted to generate an encryption of the counter value and the unique identifier, using the encryption key. The attendance device may have a receiver for receiving a registration signal from the server and update packet data including a new encryption key. The device may have a system clock which is synchronised with the system time of the server, with the counter representing a difference between the system time and a stored registration time. The attendance device may have a battery for power be operable to encrypt an indication of a battery power level with the encryption key. The device may have a display and an input button used to initiate and display the encryption. The displayed encryption code can be returned to a management facility which can decrypt the code. The device can be used to verify the attendance of a person, (employee, security guard or cleaner) at a particular location at a particular time. |
