You hand your key to someone at the hardware store, and they won’t copy it. “It says Do Not Duplicate.” You leave empty-handed, assuming there’s a law against it.
There isn’t. That stamp is a request, not a regulation. And understanding the difference could change how you think about who has access to your property.
Can You Legally Duplicate a Do Not Duplicate Key in Florida?
There’s no law in Florida, California, or any other state that makes it illegal to duplicate a key with this stamp. It carries zero legal weight.
Big box stores like Home Depot have a do not duplicate key policy, but that’s a company rule to avoid liability. It’s not because they’re required to refuse. A locksmith with the right key blank can make you a copy without any legal issue.
Why Do Keys Say “Do Not Duplicate” in the First Place?
Property managers started using this stamp decades ago as a cheap deterrent. The thinking: maybe a former tenant or fired employee will see those words and decide not to bother making a copy.
It relies on the honor system. Nothing more. The Associated Locksmiths of America has said publicly that this marking provides a “false sense of security” because the keys can still be copied by anyone willing to try.
Restricted vs. Unrestricted Keys: What’s the Difference?
If the stamp doesn’t stop duplication, what does? Restricted key systems.
| Feature | “Do Not Duplicate” Key | Restricted/Patented Key |
| Can be copied? | Yes, by any locksmith or hardware store | Only by authorized dealers |
| Legal protection? | None | Protected by U.S. patent law |
| ID required for copies? | No | Yes, plus signature card verification |
| Key blank availability | Widely available | Controlled by manufacturer |
| Penalty for unauthorized copy | None | Up to $10,000 |
What Does a Patented Key Look Like?
Patented keys look noticeably different from standard house keys. You might see dimples instead of traditional teeth, cuts on multiple sides of the blade, or unusual angles that don’t match anything at a typical kiosk.
Brands like Medeco, Mul-T-Lock, and Abloy use these designs. The manufacturer’s name is usually stamped on the bow (the part you hold), often with a serial number. If your key looks “weird” compared to a normal house key, it might be restricted.
How to Get a Copy of a Restricted Key
You can’t just walk into any store. Here’s the process:
- Find an authorized dealer for your specific key system
- Bring valid ID
- Provide your signature card (issued with the original lock)
- The dealer verifies you’re authorized before cutting
This is actual key control. Every copy traces back to a documented request. If an unauthorized key surfaces, there’s a paper trail.
Trying to get Medeco key duplication without a card? It won’t happen at a legitimate dealer. The whole point of the system is controlled access.
Keys That Can’t Be Copied at Hardware Stores
- Transponder keys: Contains a chip that must be programmed to your vehicle
- VATS keys (older GM vehicles): Has a resistor pellet that must match the car’s system
- Dimple or four-sided keys: Requires equipment most stores don’t have
- Post Office box keys: Federal law restricts duplication
- Keys marked “U.S. Property”: Government-issued, legally restricted
- Patented high-security keys: Blanks only available to authorized dealers
Should You Upgrade From “Do Not Duplicate” Keys?
It depends on what you’re protecting. For a garden shed, the stamp is probably fine. For a commercial building with employee turnover, rental units, or anywhere storing valuable inventory, a restricted system makes more sense.
The upfront cost is higher. But you stop worrying about former employees or tenants who might have made copies you don’t know about. High-security lock systems give you documented control over every key in circulation.
Quick Takeaways on Do Not Duplicate Keys and Your Security Options
“Do Not Duplicate” is a suggestion, not a law in Florida. Anyone can copy that key if they have the blank and don’t mind ignoring the stamp. If you actually need to control who has copies, restricted keys with patent protection are the way to do it.
Need a spare key made, or want to talk through your options for better key control? Door N Key offers professional key duplication services throughout West Palm Beach and Palm Beach County.