Multi-locking device using random password

A multi-locking device comprising:

• a locking device management unit configured to, when a user requests granting of the right to open/close a door, convert information on the granted right to open/close the door into a Quick Response (QR) code, output the QR code, provide the QR code to the user, and store the information;
• a door locking device configured to receive the information on the granted right to open/close the door from the locking device management unit;
• and
• a QR code reader configured to receive the QR code from the user and provide the QR code to the locking device management unit,
• wherein the door locking device further includes an opening/closing button and an opening/closing driving unit, and when information on the provided QR code matches the information on the granted right to open/close the door stored in the locking device management unit so that the door locking device receives the right to open/close the door from the locking device management unit, and when the opening/closing button is manipulated, the opening/closing driving unit is driven to open/close the door,
• wherein:
• N concurrent users (here, N is a natural number) use the door;
• and
• the door locking device includes N opening/closing buttons and one opening/closing driving unit.