Bilock is a high-security keying system designed and manufactured by Australian Lock Company Pty Ltd, is advertised to be bump proof, pick resistant, and drill resistant.
The Bilock cylinder uses a patented locking system with two locking sidebars, 12 pins and, depending on version, a trigger pin to release the side bar. The key design is a U shape profile with six cuts on each side of the key along with a central roller to activate the trigger pin in the front and center of the cylinder. In order for the lock to operate, the key must be fully inserted, allowing the dual sidebars to enter the pins, provided the pins were raised to the correct height, thereby freeing the cylinder core for rotation. The cylinder does not use the traditional top and bottom pin combination, relying instead only on the holes in the side of the pins. Many pins have a dummy hole which will trap the sidebar pin if any turning pressure is applied to the lock with the pin in the incorrect position, preventing the lock from opening. Due to the lack of top pins, lock-bumping is theoretically impossible.