The problem

Just about every key lock in the world today has the same fundamental flaw. They accept input (a key, or a lockpicking tool) from the outside world, and they test if that input is correct at the same time. This flaw opens up two kinds of vulnerabilities.

  1. Nearly every lock mechanism will leak information to a skilled attacker about its correct key. A lockpicker can feel when a lock's pins (or discs, wafers, levers, etc.) have been set in the correct position, and many locks will reveal the shape of their correct key to impressioning techniques.
  2. Most lock mechanisms can be made to bias their parts toward their correct positions. Raking, snapping, and bumping are among the many techniques that take advantage of this.

The solution

Some locks are more difficult to pick than others. Some have more perfect tolerances, or more positions, or keyways that are more difficult to fit tools into, or parts that move in unusual ways, or parts designed to mislead pickers, and so on. But these are only incremental improvements, and don't address the fundamental flaw.

The solution is to make it so that the two steps- accepting input, and testing that input- can never happen at the same time. When those two steps cannot interact with each other, a well-designed lock will never reveal information about the correct positions of its individual parts, nor can they be made to 'fall into' their unlocked positions through manipulation.

The implementation

Each position in this lock has a bottom pin, five thin master pins, and a special top pin. Key bitting is determined by the location of the notches in the sides of the top pins. When the plug is in the neutral position, there is nothing touching these notches, and so there is no way to feel where they are by manipulating the lock.

When a key is inserted, it will lift some number of the master pins in each position up past the shear line. Any key, right or wrong, can then turn partway. With six positions, each of which can be at one of six heights, there are 46,656 possible keys.

Once the plug is turned even a little, the holes in the plug no longer align with the holes in the body, and the mechanism inside the lock is effectively isolated from the outside world. So long as the plug is partially turned, no tools can manipulate the mechanism inside nor be used to learn anything about it. At the same time, the lock body now contains all the information it needs in order to verify the key.

Only in this isolated state, as the key continues to turn, the topbar mechanism will move to test if the key is correct. If the pins are all at the correct height, the topbar can move freely, and the plug can turn unimpeded. Otherwise, the topbar collides with one or more of the top pins and prevents the plug from turning any farther.

With a mechanism that ensures that the steps of input and verification are strictly separated, this lock is invulnerable to existing nondestructive attacks.

Video explaination:

Get in touch

I plan to make a limited number of samples of this lock, to send to prominent corners of the security and locksport communities, and to sell to interested individuals. I welcome all to analyze, discuss, and attempt to defeat my design.

Please be aware that this lock is only a demonstration of the mechanism, and cannot be used to secure doors, chains, or anything else. My hope is that a real lock manufacturer will want to incorporate this design into their products.

You can contact me at

Patent pending.

Buy one

These are made in small batches in my home workshop, then fitted and assembled by hand. This process takes some time, but I'll do my best to keep the wait for orders as short as I can.

I'll be selling these for $250 each. Shipping inside the US is free, but if you're outside the US, please get in touch and I'll get you a quote.

Update, June 8th 2022: I am out of stock again! It will probably be around four weeks before I'm able to make more.