A method for changing parameter values of a computer system without changing security properties, the method comprising: receiving , by a processor, a request to change a system configuration of the computer system; identifying , based on the request to change the system configuration, at least one parameter in a secure storage of parameters relating to system configurations of the computer system; receiving, by the processor, instructions to change the identified at least one parameter from initiators; initiating , by the processor, a transaction to change the identified at least one parameter (120; 220) based on the received instructions and forming a current copy of the state of the parameters in the secure storage; verifying whether the change to the identified at least one parameter is allowable and verifying consistency between the identified at least one parameter and at least one unchanged parameter in the secure storage of parameters that is related to the identified at least one parameter by evaluating whether the change conforms to rules of security policies by using the current copy of the state of the parameters at the time of making the change; performing an analysis , by the processor, to determine whether the initiated transaction to change the identified at least one parameter will lower at least one security level of the computer system based on identified collisions between the identified at least one parameter and the at least one unchanged parameter; generating, by the processor, results of the analysis, wherein, if one or more collisions are identified, the results include information on the identified collisions and information on correction variants to eliminate the identified collisions; and executing , by the processor, the change of the identified at least one parameter related to the system configuration when no collisions between the identified at least one parameter and the at least one unchanged parameter are identified. receiving , by a processor, a request to change a system configuration of the computer system; identifying , based on the request to change the system configuration, at least one parameter in a secure storage of parameters relating to system configurations of the computer system; receiving, by the processor, instructions to change the identified at least one parameter from initiators; initiating , by the processor, a transaction to change the identified at least one parameter (120; 220) based on the received instructions and forming a current copy of the state of the parameters in the secure storage; verifying whether the change to the identified at least one parameter is allowable and verifying consistency between the identified at least one parameter and at least one unchanged parameter in the secure storage of parameters that is related to the identified at least one parameter by evaluating whether the change conforms to rules of security policies by using the current copy of the state of the parameters at the time of making the change; performing an analysis , by the processor, to determine whether the initiated transaction to change the identified at least one parameter will lower at least one security level of the computer system based on identified collisions between the identified at least one parameter and the at least one unchanged parameter; generating, by the processor, results of the analysis, wherein, if one or more collisions are identified, the results include information on the identified collisions and information on correction variants to eliminate the identified collisions; and executing , by the processor, the change of the identified at least one parameter related to the system configuration when no collisions between the identified at least one parameter and the at least one unchanged parameter are identified. <EOS>