A locking mechanism is provided for a lock body and a rotatable key plug. The locking mechanism comprises pins having recesses, each of the pins adapted to be disposed in pin bores in the key plug for reciprocal and rotational movement. An elongated spring member simultaneously engages and biases the pins toward a keyway in the key plug. A locking bar moves between a first position and a second position where at least a portion of the locking bar is received in the recesses in the pins. The locking bar is prevented from moving to the second position unless the pins are in a position where the recesses are aligned with the locking bar. Upon insertion of a key in the keyway the pins are moved axially or rotated for aligning the recesses in the pins with the locking bar so the key can rotate the key plug.