A lock and key combination including - a cylinder lock with a rotatable key plug having a key slot for receiving a flat key blade, - a key with said flat key blade, and - at least two side locking tumblers (201a, 201b; 301, 302; 401, 402) in said cylinder lock, said side locking tumblers being guided for elevational and possibly also rotational movement in associated chambers in said key plug and having transverse fingers (211a, 211b; 311, 312; 411, 412a, 412b) projecting into said key slot for engagement with said key blade, upon inserting said key into said key slot, and - an associated code pattern in a side recess (115, 118) of said key blade for engagement with said transverse fingers and positioning said side locking tumblers into positions that allow said key plug to rotate in said cylinder lock upon inserting a correctly coded key into the key slot, - said fingers having different lengths, at least one having a first, short length and at least one having a second, long length, - the short fingers engaging with a primary code surface having a number of first code surface portions at an external portion of said side recess of the key blade, and the long fingers engaging with a secondary code surface having a number of second code surface portions at an internal, deeper portion of said side recess of the key blade, characterized in that - said transverse fingers are each located at a specific longitudinal position which is centered in relation to or is longitudinally displaced from a transverse plane extending through a central axis of the associated chamber accommodating said side locking tumbler, and - said first and second code surface portions of said key are specifically distributed longitudinally in relation to predetermined locations along said key blade, namely being centered or longitudinally displaced relative to said predetermined locations, so as to allow said transverse fingers to be seated on said first and second code surface portions (111, 112; 141, 142; 151, 152) upon inserting the key into the key slot, - wherein said first and second code surface portions are located at distinct positions which are generally varied or separated in three dimensions in said flat key blade, namely - in a direction upwards and downwards in a vertical plane defining said flat key blade, - in a depth direction which is perpendicular to said vertical plane, and - in a longitudinal direction along said key blade, such that a compact code pattern with an increased number of possible code combinations is formed on the key blade. - a cylinder lock with a rotatable key plug having a key slot for receiving a flat key blade, - a key with said flat key blade, and - at least two side locking tumblers (201a, 201b; 301, 302; 401, 402) in said cylinder lock, said side locking tumblers being guided for elevational and possibly also rotational movement in associated chambers in said key plug and having transverse fingers (211a, 211b; 311, 312; 411, 412a, 412b) projecting into said key slot for engagement with said key blade, upon inserting said key into said key slot, and - an associated code pattern in a side recess (115, 118) of said key blade for engagement with said transverse fingers and positioning said side locking tumblers into positions that allow said key plug to rotate in said cylinder lock upon inserting a correctly coded key into the key slot, - said fingers having different lengths, at least one having a first, short length and at least one having a second, long length, - the short fingers engaging with a primary code surface having a number of first code surface portions at an external portion of said side recess of the key blade, and the long fingers engaging with a secondary code surface having a number of second code surface portions at an internal, deeper portion of said side recess of the key blade, characterized in that - said transverse fingers are each located at a specific longitudinal position which is centered in relation to or is longitudinally displaced from a transverse plane extending through a central axis of the associated chamber accommodating said side locking tumbler, and - said first and second code surface portions of said key are specifically distributed longitudinally in relation to predetermined locations along said key blade, namely being centered or longitudinally displaced relative to said predetermined locations, so as to allow said transverse fingers to be seated on said first and second code surface portions (111, 112; 141, 142; 151, 152) upon inserting the key into the key slot, - wherein said first and second code surface portions are located at distinct positions which are generally varied or separated in three dimensions in said flat key blade, namely - in a direction upwards and downwards in a vertical plane defining said flat key blade, - in a depth direction which is perpendicular to said vertical plane, and - in a longitudinal direction along said key blade, such that a compact code pattern with an increased number of possible code combinations is formed on the key blade.