bricking a lock

Bricking in technical parlance means to unintentionally destroy something while working on it.   This typically involves unauthorized operation, firmware flashing, etc.    It’s called bricking because it turns the sometimes-pricey object into a useless mass, a brick.  A doorstop.  A boat anchor.

There are many odd things about how locks work, and one of them is that locks can be bricked.   Since the designers assume they will be opened with a key, some locks depend on the presence of the key to hold the guts in place when the lock is open (core is rotated).  If the key is not present the pins and other parts can fall into unintended places and freeze the core in place.

A famous example of this is the Master 410 “LOTO” (lock out - tag out).   It is used by tradesmen to lock out (prevent use of) a system so s/he can work on it safely.

Rotating the 310s core after picking can be safely done to the 90deg, which is  traditional anyway.  Rotating it 180deg turns it into a bricked “rattle” with pins bouncing around inside the body.

There are a couple interesting things about the 410 (in addition to brickabilty).

plastic body

The body of this lock really is plastic.  It could be defeated by destructive measures with minimal effort.    But it’s not intended to provide physical security, it’s intended to provide operational security.  The body is brightly colored and intentionally conspicuous.  It is intended to be seen;  it signals someone is working on the system.


Master doesn’t have a great reputation in the lockpicking world but the core (the part the key goes into and allows the lock to release) is unexpectedly good.

It contains 6 pins (the parts that are moved by the proper key) rather than 4-5, and the driver pins (upper pins that are pushed above the shear line) are more complex security pins intended to thwart lockpickers.  Of course, locksport folk say “challenge accepted!”.

Since the lockpicker can’t see inside they lock (except for clear demonstration locks) they are operating on feel.  Security pins disrupt normal feel using different techniques.  Two common ones are

  • texture - serrations cut into the pin cause it to hang and drag while picking

  • shape - spools are the most common form of shaped security pin.  Instead of looking like thin rods they look a bit like dumbbells you might use for curls.  The wide-narrow-wide profile complicates tactile feedback while picking.

I tell you that to tell you this:  the 410 has 5 spools and 1 serrated pin.  This makes it more complex and can be a part of earning a “green belt” ranking in /r/lockpicking.

LockWiki entry for the Master 410 LOTO