the.com/cylinder lock
a tiny bouncer club checking every key's ID before letting the door move.
means a lock mechanism using pin-tumbler cylinders that only rotate when the correct key aligns all internal pins to the shear line.
from perfected by linus yale jr. in the 1860s, refining ancient egyptian pin-tumbler concepts into the compact brass cylinder still used today.
shear linethe invisible gap pins must align to unlock
lock pickingexploits tiny manufacturing gaps between pins
master keyswork via extra split pins in same cylinder