Patent ID: 8692652

Claim:
A system for preventing a plurality of equipment from theft, comprising: an electronic key that is configured to be carried by an operator of the equipment and stores plurality of authenticating data, each corresponding to the plurality of equipment; an authenticator that is installed at the equipment and performs authentication check as to whether the electronic key is an authorized key using stored key-checking data, when the authenticating data is outputted from the electronic key; and an electronic key copier that is provided separately from the equipment and is configured to copy the electronic key, wherein the electronic key is one of a first electronic key comprising a master ID which can be copied by the electronic key copier and a second electronic key copied from the first electronic key; the electronic key copier including a terminal device and a reader/writer connected to the terminal device, wherein the terminal device is configured to read the master ID from the first electronic key and store as a copy ID, to write the copy ID into the second electronic key so that the second electronic key is copied from the first electronic key, and the terminal device is further configured to write the stored copy ID into the first electronic key, while the terminal device is configured to inhibit additional copying of the second electronic key.