By: Arron Ewen

The quick answer to this common question is, yes, a key that says “Duplication Prohibited” or “Do not Duplicate” can still be copied. However, the truth is not quite so simple. Some keys can still be copied, and others can’t, some require a locksmith to copy them, and others require a specific company to copy the key. We will be dissecting this seemingly straightforward yet complex question. Grab your favorite drink or snack and stick around for just a moment while I go over the difference between restricted keys and keys that say, “Do not Duplicate.”

Many managers and business owners share a common concern when it comes to giving keys to their employees. The most common concern is with their employees making copies of keys that enter sections of the workplace. They will come to me and ask how they can prevent this and typically ask if a DnD, or Do Not Duplicate key is available. We can stamp any key of our choosing with Do Not Duplicate. But does it really stop anybody from copying the key? The answer is both yes and no. Most hardware stores will see that mark as a liability and will say they are not allowed, and recommend contacting a local locksmith. This is where it gets complicated. If a locksmith can acquire or has the key blank you need in stock, they will not hesitate to copy your key. This is due mostly to the fact that there are no legal repercussions for copying a DnD key. The ugly truth is that most locksmiths don’t care what the key says. if they can copy it, they may do so without hesitation.

So, is there a way to truly prevent a key from being duplicated? This brings us to restricted keyways.

What is a restricted keyway?

A restricted keyway is a key way that a company has patented and only they have the right to purchase cylinders or keys for that keyway. For example, John Doe may have a patent on a certain keyway for Schlage Primus, a high-security keyway. If all of your locks use that keyway and you give those keys to your employees, the only company that can purchase blanks will be John Doe. In order to purchase cylinders or keys, you must produce a card that is given to you when you purchased the cylinders initially and present it to John Doe. If an employee from your company comes in asking for keys, they will not be allowed to purchase keys or cylinders without the card; Additionally, they must be listed as an authorized purchaser and must produce a valid photo ID to verify the purchase. In this system, you have true control over your keys and can successfully prevent your employees from making copies of your key. But there is a catch.

Your building has 10 doors that use a restricted key patented by John Doe. If John Doe goes out of business, you have no choice but to replace every cylinder and key just so you can have additional keys for new employees. This is a problem that you will face with any company with any kind of restricted key whether it be Mul-T-Lock, Medeco, or Schlage just to name a few. While there are ways to get around the restriction, it will ultimately be the choice of the company that owns the patent.

So, can a DnD key be copied? Yes, unless it is a restricted key. An alternative to restricted keys would be an electronic access control system. Whether you use keypads or card readers, it is significantly more cost-effective long term when it comes to requiring more codes or cards. There are other benefits to access control beyond purchasing cards or adding codes. To learn more about access control, please see any of our articles regarding access control. A great starting point is our article titled “What is Access Control?” where we give a brief synopsis of the purpose and various forms of access control. Check back often for more articles where we answer your questions and offer tips from our master locksmiths gathered from almost a century of being in business.