Keyed device for operating locks, incorporating euro profile i cylinders, suitable for installation on security doors, armoured doors and the like, and comprising at least one cylinder-operated deadbolt, where the cylinder comprises a cam that can be rotated in either direction, respectively to open or close at least one deadbolt, and where the device in question comprises: - one mechanism for operating the cam comprising: an actuator plug situated inside the euro profile cylinder i and coaxial with the rotation axis of the cam, which causes the cam to rotate; a manipulator head, connected to the actuator plug, and which causes the plug to rotate; mechanical combination means for blocking and releasing the rotation of the manipulator head and the connected actuator plug; - an opening/closing assembly, accessible from the exterior of the security doors, armoured doors and the like, for operating the manipulator head and the mechanical combination means, where the opening/closing assembly comprises: an outer shell, incorporating an axial pass-through cylindrical seat characterized in that the axial pass-through cylindrical seat houses a rotor coaxial with the manipulator head and the actuator plug, where the rotor is able to slide axially toward the manipulator head, in opposition to the spring-loaded components which retain it, when at rest, against a shoulder within the cylindrical seat; a defender block, for impeding external access to the manipulator head, supported by a pin inside the rotor, with the ability to rotate on an axis perpendicular to the rotation of the rotor, where the defender block is partially accessible externally and close to the manipulator head with its corresponding internal part, and where the defender block comprises a first profiled face that can be stably paired with a removable flat key, and a second profiled face, diametrically opposite to the first, that can be provisionally paired with a locking/unlocking tool, and where the defender block is able to rotate between at least two characteristic positions, one where the first profiled face is turned outward and can receive the flat key, and another where the first profiled face is turned toward the manipulator head while the second profiled face is turned outward and can receive the locking/unlocking tool, which can be manually operated on to achieve: the axial translation of the rotor - defender block - flat key assembly (22, 25, 26), so that the key engages with the mechanical combination means for releasing the rotation of the manipulator head; the rotation, in one or the other direction, of the rotor-defender block - flat key - manipulator head - actuator plug assembly (22, 25, 26, 11, 10), with consequent rotation in the same direction of the cam to open or close the lock. - one mechanism for operating the cam comprising: an actuator plug situated inside the euro profile cylinder i and coaxial with the rotation axis of the cam, which causes the cam to rotate; a manipulator head, connected to the actuator plug, and which causes the plug to rotate; mechanical combination means for blocking and releasing the rotation of the manipulator head and the connected actuator plug; - an opening/closing assembly, accessible from the exterior of the security doors, armoured doors and the like, for operating the manipulator head and the mechanical combination means, where the opening/closing assembly comprises: an outer shell, incorporating an axial pass-through cylindrical seat characterized in that