Key management & master-key systems

A master-key system organises "who opens what" in a building: each door has its own key, and "pass" keys open several doors according to defined rights. Useful in apartment buildings, co-ownerships, companies, hotels or large homes.

Grand master key (GMK): one key that opens the entire system. Sub-master key (SMK): a key that opens only part of it (one floor, one department). Central opening (CO): the opposite of a grand master key — several different keys open one common cylinder (building entrance, cellars, parking) without opening the neighbour's door.

Several cylinders that share the same key: they all open with the same key. Handy to limit the number of keys (front door + cellar + garage, or every classroom in a school).

For residential use, central opening is preferred: each apartment's key also opens the common areas (hall, bin room) without opening the other flats. A grand master key on dwellings is avoided.

A grand master key on dwellings can void the cylinder's A2P certification, as it represents a vulnerability. On housing, it's better to avoid the grand master key, or to control it strictly (sealed in a safe, emergency use only).

Patented reversible keys cannot be copied without an ownership card and do not allow the system to be "decoded". A much higher level of security than traditional toothed keys.

A master-key system has no limited lifespan: it stays fully functional as long as the manufacturer keeps producing the cylinder and key profile. Some models have been manufactured continuously for over 50 years. As long as the model is available, the system remains extendable and can be replenished with new cylinders.

Contact us with your requirements (number of doors, desired access levels): we design your locking plan on quotation.