A locking system of a cylinder lock and a shank of a key, which comprises a base body, which is provided with a longitudinal cylindrical opening, in which a set of disk tumblers is arranged rotatably about a longitudinal axis of the lock, where the disc tumblers are provided with a central opening for insertion and rotation of the shank of the key and on the circumference of the central opening the disc thumblers are provided with at least one coding projection, while and on its outer circumference the disc thumblers are provided with at least one coding cut-out for a latch, whereby the shank of the key is formed by a longitudinal plate-shaped body which is defined by a pair of opposite side surfaces defining the width of the shank and by a pair of opposite upper surfaces defining the height of the shank and the shank of the key is provided with at least one coding surface, which is adapted to interact with at least one coding projection on the disc tumbler for defined rotation of the disc tumbler in the base body about the longitudinal axis of the lock by at least one coding cut-out on the disc tumbler to a position opposite the latch, characterized in that on the shank of the key is formed at least one shifted coding surface which is situated on the shank of the key in the direction of the width of the shank at a distance (ΔT 5) from the edge surface of the shank of the key to the depth of the material of the shank of the key, and at least one disc tumbler is provided with at least one shifted coding cut-out which is shifted on the outer circumference of the disc tumbler by an angle (Δα 3) relative to the position, in which this shifted coding cut-out would be for coordination with the coding surface situated on the edge surface of the shank of the key, while shifting of the shifted coding surface and shifting of the shifted coding cut-out are coordinated for increase in the number of locking combinations and between every two adjacent disc tumblers is situated spring disc adapted to separate adjacent disc tumblers and to resiliently define axial clearances in the direction of the longitudinal axis of the lock within the system of the disc tumblers and on the base body is formed a system of axial stops for a defined group of disc tumblers and the spring discs associated with them for further improving the definition of the axial clearances in the longitudinal axis of the lock within the system of the disc tumblers. a base body, which is provided with a longitudinal cylindrical opening, in which a set of disk tumblers is arranged rotatably about a longitudinal axis of the lock, where the disc tumblers are provided with a central opening for insertion and rotation of the shank of the key and on the circumference of the central opening the disc thumblers are provided with at least one coding projection, while and on its outer circumference the disc thumblers are provided with at least one coding cut-out for a latch, whereby the shank of the key is formed by a longitudinal plate-shaped body which is defined by a pair of opposite side surfaces defining the width of the shank and by a pair of opposite upper surfaces defining the height of the shank and the shank of the key is provided with at least one coding surface, which is adapted to interact with at least one coding projection on the disc tumbler for defined rotation of the disc tumbler in the base body about the longitudinal axis of the lock by at least one coding cut-out on the disc tumbler to a position opposite the latch, characterized in that on the shank of the key is formed at least one shifted coding surface which is situated on the shank of the key in the direction of the width of the shank at a distance (ΔT 5) from the edge surface of the shank of the key to the depth of the material of the shank of the key, and at least one disc tumbler is provided with at least one shifted coding cut-out which is shifted on the outer circumference of the disc tumbler by an angle (Δα 3) relative to the position, in which this shifted coding cut-out would be for coordination with the coding surface situated on the edge surface of the shank of the key, while shifting of the shifted coding surface and shifting of the shifted coding cut-out are coordinated for increase in the number of locking combinations and between every two adjacent disc tumblers is situated spring disc adapted to separate adjacent disc tumblers and to resiliently define axial clearances in the direction of the longitudinal axis of the lock within the system of the disc tumblers and on the base body is formed a system of axial stops for a defined group of disc tumblers and the spring discs associated with them for further improving the definition of the axial clearances in the longitudinal axis of the lock within the system of the disc tumblers.