Proposed invention is an alarm device for protecting various type of locks of premises, buildings, apartments, rooms, vehicles, safes, money terminals and for other objects by means of timely, more early informing, interaction with alarm system or digital-electronic device of persons observing protected object in result of attempts of burglary, unauthorized opening, damaging or even preliminary studying the lock by attacker.

A system may include a lock assembly having secured and unsecured conditions and having an opening for receiving a lock actuating object. An access restriction element may be positionable with respect to the lock assembly to affect access to the opening of the lock assembly. The access restriction element may have at least two conditions, a blocking condition in which the access restriction element at least partially obstructs access to the opening of the lock assembly and an access condition in which the access restriction element is configured to permit access to the opening of the lock assembly. The system may also include an access detection assembly configured to detect attempted access to the opening of the lock assembly by sensing changing of the access restriction element from the blocking condition to the access condition.

A lockset is provided with a sensor assembly for detecting tampering with the cylinder. A lock cylinder with a cylinder body and a cylinder plug disposed in the cylinder body is provided. The cylinder plug is configured to deform and/or separate from the cylinder body when a sufficient force is applied. A sensor assembly is provided that detects when the cylinder plug deforms and/or separates from the cylinder body. In some embodiments, the sensor assembly could detect when the cylinder plug deforms and/or separates from the cylinder body with a strain gauge, a continuity circuit, a micro-switch, an optical sensor, an accelerometer and/or a contact microphone.