| 摘要 |
PROBLEM TO BE SOLVED: To secure safety by varying a code every time it is sent; and determine whether a door is open or closed through one-way communications alone. SOLUTION: In a transmitter 11, the number of requests to open or close the door is counted by a transmission counter 112. A seed value in a seed storage part 111 is renewed at each transmission and encoded by an encoding part 113, with this encoded value being transmitted by a transmitting part 114, together with the data of the transmission counter. In a receiver 12, the number of times of transmission during the previous proper process and data for checking are retained respectively in a transmission counter 121 and a seed storage part 122. The seed value is anticipated based on the data renewed by the transmission counter 121. A verifying part 126 compares the encoded seed value anticipated with the encoded seed value transmitted thereto to determine whether the door is locked or unlocked.
|
