Electronic key system, and lock-side terminal and portable terminal employed in same

An electronic key system, comprising:

• a lock-side terminal mounted in a locked object, including
• a first information processing unit having an electronic key generation storage that stores at random an electronic key including function information defining an operable function to the locked object, and capable of at least locking and unlocking the locked object by receiving a request from one portable terminal, and a first wireless transceiver unit capable of sending and receiving various pieces of information including the electronic key to and from one portable terminal;
• a portable terminal including a second wireless transceiver unit capable of sending and receiving information to and from the lock-side terminal and the other portable terminals, and a second information processing unit including an electronic key storage that stores the electronic key received from the lock-side terminal via the second wireless transceiver unit;
• another portable terminal including a third wireless transceiver unit capable of sending and receiving information to and from the one lock-side terminal, and a third information processing unit having an electronic key storage,
• wherein the first information processing unit instructs the first wireless transceiver unit to send the electronic key previously stored to the one portable terminal when receiving the request from the one portable terminal via the first wireless transceiver unit,
• wherein when receiving a request to transfer or copy the electronic key stored in the electronic key storage to the other portable terminal, the second information processing unit instructs the second wireless transceiver unit to send the request to transfer or copy the electronic key with function limitation information in which only a selected function is enabled to the other portable terminal, and in a case where there is a response of transfer or copy possible with respect to the request to transfer or copy the key from the other terminal via the second wireless transceiver unit, the second information processing unit instructs the second wireless transceiver unit to transfer or copy the electronic key to the other portable terminal,
• wherein when receiving the request to transfer or copy the electronic key from the one portable terminal via the third wireless transceiver unit, the third information processing unit determines whether or not the transfer or copy is possible, and sends to the one portable terminal the response of transfer or copy possible, or transfer or copy impossible based on a result of the determination, and when the electronic key is transferred or copied from the one portable terminal via the third wireless transceiver unit, the transferred or copied electronic key is stored in the electronic key storage of the third information processing unit.