1. A computer system, providing means for security in a computerized control system ( 1 ), the computer system comprising a workstation ( 4 ); a software system representing a real world entity ( 10, 11 ) as a first software object ( 31 ); a system for control and/or supervision of the real world entity; means for inserting a software object in a hierarchical structure; means for identification of an individual user at the time of log-in to said computer system; means for identifying the individual user during the time between log-in to log-out with a user identity; characterized in that the first software object ( 31 ) is inserted into at least two hierarchical structures ( 20, 21, 22 ) of software objects and the first software object inherits at least one security aspect ( 28 ) from a second software object ( 23 ), where the second software object ( 23 ) is inserted at a higher position than the first software object in one of said hierarchical structures, and the first software object inherits at least one security aspect ( 29 ) from a third software object ( 24 ), where the third software object is inserted at a higher position than the first software object in one of said hierarchical structures; a current security of the first software object ( 31 ) is based on at least two security aspects ( 28, 29 ) associated with the first software object, inherited through at least two hierarchical structures; a current user authority to access at least one aspect of the first software object is based on at least two security aspects ( 28, 29 ) inherited through at least two hierarchical structures in combination with the user identity in said computer system.