Can Your Keys Really Be Duplicated? The Truth About "Do Not Duplicate" Keys vs. Restricted Key Systems

Nerd Fox
Aug 24
2 min read

You’ve probably seen it before — a key stamped with “Do Not Duplicate” or “Duplication Prohibited.” Many people assume this means their key is impossible to copy. The truth? That’s not the case.

MX13 Restricted Key System — Key with Duplication Prohibited Stamp

The Reality of "Do Not Duplicate" Keys

Keys marked with "Do Not Duplicate" are not physically restricted in most cases.
A standard locksmith or hardware store can still duplicate them with ease.
The stamp is more of a request or advisory, often used by property managers or businesses to discourage unauthorized copies.

In short, if you hand one of these keys to the wrong person, chances are they can still walk into a hardware store and get a duplicate made.

Enter Restricted Key Systems

Unlike standard keys, restricted key systems like the MX13 provide true protection against unauthorized duplication. Here’s why:

Patented Key Design
- Restricted keys are patented. This means that duplication is legally controlled and cannot be performed without authorization from the system’s owner.
Unique Keyway Profiles
- These keys are cut on special keyways that are not available to the general public. A standard key-cutting machine cannot replicate them.
Authorized Duplication Only
- To duplicate a restricted key, the lock owner must request it through an authorized dealer and provide proper proof of ownership.
Tracking and Accountability
- Every issued key is tracked, so owners know exactly how many copies exist and who has them.
Enhanced Lock Security
- Restricted key cylinders often include anti-pick and anti-bump technology, providing another layer of physical protection beyond key control.

Why This Matters for Your Security

If your home, office, or rental property relies on standard keys — even those marked “Do Not Duplicate” — you’re not truly protected. Anyone who gets their hands on one of your keys can make a copy. With a restricted key system like the MX13, you have peace of mind knowing that your keys cannot be duplicated without your authorization.

Final Word

“Do Not Duplicate” is a nice thought — but it won’t stop a determined thief or an untrustworthy employee. If you’re serious about controlling access and protecting your property, a restricted key system is the only way to go.

At Lock Nerds Locksmith, we provide MX13 restricted key systems that ensure your security is in your hands — and no one else’s.