Disc-detainer lock
A disc-detainer lock, also called a disc-tumbler, Abloy lock, or simply disc lock is a high-security keyed lock that uses a set of discs similar to those used in a combination lock. The difference is that the discs are rotated by a key instead of a dial.
Mechanism
When the key is put into the lock, it rotates a set of discs with notches on them to different positions depending on the depth of the cuts in the key. The right key will line up a set of notches in a straight line, allowing a bar to fall into the notches, opening the lock. The wrong key will not put the notches in a straight line, and the bar will not fall, preventing the lock from opening. On high-end disc-detainer locks (such as Abloy), there are usually "false" notches on the disc as well. These feel like the real notch to someone trying to pick the lock, but do not allow the bar to fall. This makes it nearly impossible to pick the lock. It is possible to pick some lower-end disc-detainer locks. The disc-detainer mechanism usually does not contain any springs. This reduces the amount of wear on the cylinder.
Other websites
A YouTube video of the mechanism