Kromer protector safe lock A very rare and superb example of this high security safe lock
The design includes double-acting wafers that operate on both sides of the locking mechanism. Some wafers have cuts that interact with the key, while others serve purely deceptive purposes and do not affect operation. The number and design of the wafers constitute a key protection against lockpicking and decoding attacks, which aim to determine the internal wafer configuration to identify the required key. Crucially, the wafers must be lifted to an exact height for the lock to open.