The do not duplicate marking originated as a courtesy convention. A key manufacturer or locksmith would stamp keys for systems where the owner wanted duplication controlled, on the understanding that key cutters would honour the request.



It is a request directed at whoever might cut the key. It creates no legal obligation and there is no penalty for ignoring it. The stamp does not change the key blade profile, does not restrict the availability of blanks, and does not require anyone to check who is asking.

Blanks are freely available.

The stamp is on the key, not on the blank. A key cutter has the matching blank in stock regardless of what is stamped on the original, because the blank corresponds to a standard commercial profile used across thousands of locks.

Enforcement is voluntary and inconsistent.

Some locksmiths will decline. Many hardware stores and automated kiosks will cut it without any human seeing the stamp at all. Self-service kiosks photograph the key blade to determine cut depths and have no mechanism to read or act on a stamp.

The person copying is usually entitled to hold the key.

The staff member, tenant, or contractor with the key is not doing anything obviously wrong by getting a spare cut. They are not defeating a security system. They are ignoring a printed suggestion, often without registering that it was there.

No record exists.

Even where a copy is refused at one outlet, nothing prevents the person walking to another. Nothing is logged, so the key holder never knows a copy was attempted or made.

A restricted key system controls duplication through physical availability of the blank rather than through a request.

Patented blade profile.

The key blade geometry is protected by patent. Manufacturing blanks in that profile without a licence is a patent infringement, which gives the restriction genuine legal force.

Controlled blank distribution.

Blanks are supplied only to locksmiths authorised on that platform. A hardware store or kiosk does not have the blank and cannot obtain it.

Verification before cutting.

The authorised locksmith holds your system on file and verifies that whoever requests a copy is entitled to hold a key for that property before cutting one.

A record of every cut.

Each key issued is logged against the system, so the number of working keys in existence is a known quantity rather than an assumption.

Businesses with staff turnover.

The gap between collecting a key back and knowing no copies exist is exactly what restricted systems close.

Landlords and property managers.

Restricted keys mean an outgoing tenant cannot have left copies in circulation, which reduces the need for full rekeying at every changeover.

Strata and shared buildings.

Common area keys distributed across many residents are the hardest keys to control by any other means.

Homes with high-value contents or extensive contractor access.

Any property where a number of people have held a key over time.

Contact True Locksmith on 0421-767-767 for restricted key systems and professional key cutting across Bayside Melbourne. Neale can assess your existing hardware, set up a restricted profile, and register your system so no copy is ever cut without your authorisation. Over 30 years of experience. MLAA member and VIC Police registered. Serving Sandringham, Brighton, Brighton East, North Brighton, Beaumaris, Bentleigh, Black Rock, Caulfield, Cheltenham, Hampton, Highett, McKinnon, Mentone, Moorabbin, Mordialloc, and Parkdale.