Tag Archives: physical security

People lock their doors at night and feel protected from criminals. The scary thing most people are not aware of is locks are easy to bypass with inexpensive tools. You may think these tools are hard to obtain however I watch lock pick kits sellout at security conferences each year with attendance in the thousands. If you search the Internet for terms like “lock picking, bump keys or impressioning” you’ll find hundreds of results including video tutorials. It’s not hard for criminals to break into doors and safes. In most cases, they can do it in under a minute without leaving behind evidence the average users will notice.

Inside a common lock

The first thing you should understand is the basic concept of most locks. Common door locks contain components that sit out of line until a key is inserted. Once the components are lined up, the lock can be opened. Most lock picking tools use two tools to bypass this system. One tool applies tension to the lock while the second tool moves the plug, bolt or other components into position. Once the attacker properly positions the components the lock can be opened.

Picture of two lock picking tools I purchased at a conference for under $20

Another way attackers could bypass a common pin-tumbler lock is using a bump key. The concept uses a modified key that has cuts at their lowest depths. Attackers use a bump hammer on the inserted key by lightly tapping and applying tension. This causes kinetic energy to travel from the key to the top pins causing these pins to jump. If all top pins jump above the shear-line, the lock will open. I’ve gotten this to work with the back of a rubber screwdriver handle but it took lots of attempts.

Picture of bump keys I picked up for under $20 dollars.

Impressioning is a way to develop a permanent working key. One way this could be done is using a blank key by inserting it into a lock and applying lots of torque. The lock’s pins will leave marks on the blank key giving away their positions. The attacker can file down those locations and continue the process until the key opens the lock. This may sound time consuming however a German speaker at the 2011 Defcon conference opened an average lock using this technique in 30 seconds. Blank keys for common locks can be purchased in bulk for very little.

There are more professional ways to beat locks such as using pin guns, molding or bypassing the lock (IE using the old credit card) that I’m not covering. Many enthuses consider lock picking a hobby where locks are like puzzles to be beaten and understood. I’m not skilled in this art yet with cheap tools have opened locks at conference and other approved locations. Your best bet is to continue to use locks along with a detection defense such as an alarm or surveillance system. My neighbor relies on his dog and shotgun, which is just as effective.