Tamper-resistant lock

A tamper-resistant lock comprising an outer cylinder adapted to be mounted in an entrance barrier;

• an inner cylinder rotatably mounted in said outer cylinder;
• a plurality of top pins disposed in chambers on said outer cylinder, said top pins being urged toward said inner cylinder;
• a plurality of bottom pins disposed in chambers in said inner cylinder, said chambers in the inner and outer cylinders being in alignment when the lock is locked;
• a plurality of wafers being disposed between at least one pair of said top and bottom pins when the lock is locked;
• at least one of said wafers having a recess in its side;
• at least one wafer being disposed between said top and bottom pins in the chambers not containing at least one wafer with a recess;
• at least one said wafer in chambers not containing at least one wafer with a recess having a hole therein;
• at least one trap mounted in a chamber in the outer cylinder;
• said trap pin being urged toward the inner cylinder;
• said trap pin additionally having an extension adapted to engage the hole in said hole bearing wafer when the lock is picked;
• a ridge mounted on either said inner or outer cylinder adapted to pass through the recess in said wafer containing a recess when the lock is opened normally and to stop the rotation of the inner cylinder at the angle of engagement of said trap pin when the lock is picked.