A method for supervising the security of a computer system comprising: several elementary computer items, each elementary item being supervised in dependence on base measurements representative of predetermined states of the elementary item, and several gathering items (BIe, BIg) each gathering several elementary items, characterized in that it comprises: de termining several security indicators of different types for each supervised elementary item, each security indicator being determined according to respective functions (AMD, AME, AAM, AAG) of base measurements associated with the security indicator, wherein the determination of a security indicator of a given type for an elementary item comprises as a result of a modification of one (MBm) of the base measurements associated with the security indicator: estimating a first derived measurement according to a function of the modified base measurement (MBm) and at least another base measurement interdependent with the modified base measurement, estimating at least a second derived measurement estimated according to a function of interdependent base measurements associated with the security indicator of the given type estimating a metrics according to a function of said first and second derived measurements, and determining the security indicator of the given type according to a function dependant on at least said estimated metrics, and determining several security indicators (IA(BIe)) of different types for each gathering item, each security indicator of a given type for each gathering item being determined according to a respective function (AAIe) of the security indicators of the given type of the elementary items (BIp) gathered in the gathering item (BIe, BIg). several elementary computer items, each elementary item being supervised in dependence on base measurements representative of predetermined states of the elementary item, and several gathering items (BIe, BIg) each gathering several elementary items, termining several security indicators of different types for each supervised elementary item, each security indicator being determined according to respective functions (AMD, AME, AAM, AAG) of base measurements associated with the security indicator, wherein the determination of a security indicator of a given type for an elementary item comprises as a result of a modification of one (MBm) of the base measurements associated with the security indicator: estimating a first derived measurement according to a function of the modified base measurement (MBm) and at least another base measurement interdependent with the modified base measurement, estimating at least a second derived measurement estimated according to a function of interdependent base measurements associated with the security indicator of the given type estimating a metrics according to a function of said first and second derived measurements, and determining the security indicator of the given type according to a function dependant on at least said estimated metrics, and estimating a first derived measurement according to a function of the modified base measurement (MBm) and at least another base measurement interdependent with the modified base measurement, estimating at least a second derived measurement estimated according to a function of interdependent base measurements associated with the security indicator of the given type estimating a metrics according to a function of said first and second derived measurements, and determining the security indicator of the given type according to a function dependant on at least said estimated metrics, and determining several security indicators (IA(BIe)) of different types for each gathering item, each security indicator of a given type for each gathering item being determined according to a respective function (AAIe) of the security indicators of the given type of the elementary items (BIp) gathered in the gathering item (BIe, BIg).