Bump Keys: The Hidden Threat to Your Door Locks

What Is a Bump Key?

A bump key is a specially cut key that can open almost any standard pin tumbler lock — including most residential deadbolts. The technique was originally used by locksmiths, but it has become widely known and exploited by criminals.

How Does Bump Keying Work?

A bump key is filed down so all cuts are at the maximum depth. When inserted into a compatible lock and struck sharply (bumped) with a rubber mallet while applying slight turning pressure, the impact causes all the key pins to momentarily jump upward. For a split second, the gap between each key pin and driver pin aligns at the shear line — allowing the cylinder to rotate and the lock to open.

Why Is This a Threat?

The technique works on an estimated 90% of standard pin tumbler locks sold in the U.S. A bump key can be made from any hardware store key blank, requires minimal practice to use effectively, and — critically — leaves no signs of forced entry. It's virtually undetectable after the fact.

How to Protect Against Bump Key Attacks

Anti-Bump Locks

Many premium lock manufacturers now offer bump-resistant or bump-proof locks. These use modified pin configurations (such as disc detainer pins or sidebar mechanisms) that cannot be manipulated through the bumping technique.

High-Security Lock Brands

• Medeco: Uses rotating pins that must align both vertically and rotationally
• Mul-T-Lock: Telescoping pins inside a secondary locking element
• ASSA Abloy: Multiple patented anti-manipulation features

Additional Measures

• Security cameras at entry points
• Secondary door bolts or chains
• Alarm systems with door sensors

Get a Bump-Resistant Lock Installed

Provo Locksmith UT supplies and installs bump-resistant locks for residential and commercial customers across Salt Lake Valley. Call us at (385) 283-6134 to upgrade your security today.