To provide a lock system, a locking and unlocking method, and a locking device for reinforcing countermeasures to prevent crime without using a high degree cipher function irrespective of use of a key incorporating an IC tag.
In this lock system, the key 1 includes the IC tag 11 capable of storing a key value and reading or rewriting it when a closed circuit is formed by mutual engagement of the key 1 and a first lock 2. The first lock 2 has a means for generating a new key value, storing it, and locking the first lock 2 when the first lock 2 is unlocked and the key 1 is at a locking position while it is engaged with the first lock 2, a means for writing the generated key value into the IC tag 11, a means for reading the key value stored in the IC tag 11 when the first lock 2 is locked and the key 1 is at an unlocking position while it is engaged with the first lock 2, and a means for comparing the read key value with the stored key value and unlocking the first lock 2 when these values agree.
Toshifumi Onuki
Akihiko Eguchi
Kazuhiko Naito
Tetsuo Tsuchiya