High-security locks explained: what actually makes a lock high-security

"High-security" appears on a lot of packaging. In the lock trade it has a more specific meaning. A true high-security lock resists the main ways a lock is attacked, and it controls who can make copies of your key.

Standard locks and their weak points

A typical residential lock is a pin tumbler cylinder with five or six pins. It keeps honest people honest, but it has known weaknesses:

• Picking: manipulating the pins one by one with tools.
• Bumping: using a specially cut "bump key" to jolt the pins into place.
• Drilling: destroying the cylinder so it can be turned.
• Key copying: anyone with your key can have it copied at a kiosk in minutes.

What high-security locks add

• Pick and bump resistance. Extra locking elements such as side bars, rotating pins or secondary pins must all be correct at once. This makes picking and bumping far harder.
• Drill resistance. Hardened steel inserts protect the areas an attacker would drill.
• Key control. Keys use patented profiles that are not sold as blanks to the public. Copies can only be made by an authorized dealer, usually with an ID card that proves you are the registered owner.

Key control is often the biggest benefit. With a standard key, you never really know how many copies exist. With a restricted key system, you do.

The standards behind the claims

In North America, high-security cylinders are tested against standards such as UL 437 and ANSI/BHMA A156.30. These include timed attacks by picking, drilling and forcing. If a product claims to be high-security, look for these standards on the spec sheet.

Who needs one?

• Homes where many people have had keys over the years.
• Businesses with staff turnover, cash on site or sensitive records.
• Strata and property managers who need to know exactly which keys exist.
• Anyone protecting something valuable: a home office, a wine room or a gun cabinet.

Don't forget the door

A high-security cylinder on a weak door is like a bank vault lock on a garden shed. The strike plate, the frame and the hinges all need to hold up too. Good security is always a system, not a single part.