High security lock and key blade combination

A cylinder lock (1) and key (2) combination, said key (2) comprising a key blade (200) having, at a side surface (201) thereof, a longitudinally extending coded side surface (203) with longitudinally spaced code surface portions each representing an element of a key code, and said cylinder lock (1) comprising

• a cylinder shell (140),
• a key plug (130) which is rotatably mounted in said shell,
• a longitudinal key slot (100) extending along said key plug in parallel to the rotational axis thereof for receiving said key blade (200),
• at least two side tumblers (113, 114) in said key plug for locking said key plug against rotation relative to said cylinder shell, unless a correctly coded key is inserted into said key slot, each side tumbler being provided with a contact finger (115, 116) reaching sideways into said key slot so as to engage with said coded surface (203) of a properly shaped key blade being inserted into said key slot, and
• at least one side cavity (120) located at a transversal side of said key slot (100) in said key plug (130), said at least one side cavity accommodating and guiding said side tumblers for elevational movement therein, wherein:
• said at least two side tumblers are distributed pair-wise, with two adjacent side tumblers (113, 114) located in a respective side cavity on the same side of said key slot,
• said adjacent side tumblers (113, 114) in each pair being linearly guided but independently movable in the respective side cavity so as to be individually displaced linearly into respective elevational positions, and
• said contact fingers (115, 116) on the adjacent side tumblers in each pair having contact portions facing in the same direction and being axially separated in the longitudinal direction of the key plug such that these contact fingers are located at a longitudinal distance from each other on the same side of said key slot and will be positioned at elevationally specific and generally different code levels when being engaged by two neighbouring, longitudinally spaced code surface portions (204, 205) of said coded surface (203) upon insertion of said key blade (200) into said key slot (100),
• whereby said at least two side tumblers (113, 114) are displaceable, upon insertion of said key blade into said key slot, into individually specific elevational code positions, and each set of such elevational code positions representing a different key code with an increased number of code elements, a pair of side tumblers corresponding to two code elements.