Abstract: The invention relates to a tamper-resistant lock. The improved lock incorporates metal wafers which rest on the bottom pins in the inner cylinder of a cylindrical key lock. The wafers and the pins upon which they rest alternately incorporate holes in their topside. The wafers and the bottom pins cooperate with trap pins housed in the outer cylinder of the lock at a 45.degree. angle from the vertical insertion position of the key. The trap pins are urged into the holes in the wafers and bottom pins when tampering occurs. This apparatus prevents both the picking or impressioning of the lock, common alternative techniques for opening a key lock without the key. The improved lock also incorporates a feature to prevent unauthorized opening by rapid spinning of the lock by a spring-propelled insert placed into the lock cylinder after it has been picked.