Method for the project-related authentication of a device in a control system for a technical installation in the context of an engineering project, wherein the control system has at least one local registration authority , at least one software inventory and one certification authority embodied on a project-related basis with a first hierarchy and a second hierarchy, wherein the first hierarchy is embodied and provided to issue project-related device certificates for devices , and wherein the second hierarchy is embodied and provided to issue project-related operational certificates for devices , the method comprising the following steps: a) in the context of an authentication of the device within the control system , establishing information by way of the at least one local registration authority to see which communication protocols are supported by the device and are active; b) in the event that the local registration authority has verified that a particular project-related device certificate is supported by the device and is active, requesting the project-related device certificate at the first hierarchy of the certification authority by way of the local registration authority ; c) storing the project-related device certificate in a subinventory of the software inventory of the control system assigned to the engineering project; d) requesting a project-related operational certificate by way of a device at the local registration authority ; e) checking, by way of the local registration authority , whether a corresponding project-related device certificate is stored in a subinventory of the software inventory of the control system assigned to the engineering project for the device making the request in the context of the engineering project in which the device is making the request; f) in the event that the local registration authority has verified that a particular project-related operational certificate is supported by the device and is active, requesting a project-related operational certificate at the first hierarchy of the certification authority by way of the local registration authority ; g) forwarding the project-related operational certificate to the device . a) in the context of an authentication of the device within the control system , establishing information by way of the at least one local registration authority to see which communication protocols are supported by the device and are active; b) in the event that the local registration authority has verified that a particular project-related device certificate is supported by the device and is active, requesting the project-related device certificate at the first hierarchy of the certification authority by way of the local registration authority ; c) storing the project-related device certificate in a subinventory of the software inventory of the control system assigned to the engineering project; d) requesting a project-related operational certificate by way of a device at the local registration authority ; e) checking, by way of the local registration authority , whether a corresponding project-related device certificate is stored in a subinventory of the software inventory of the control system assigned to the engineering project for the device making the request in the context of the engineering project in which the device is making the request; f) in the event that the local registration authority has verified that a particular project-related operational certificate is supported by the device and is active, requesting a project-related operational certificate at the first hierarchy of the certification authority by way of the local registration authority ; g) forwarding the project-related operational certificate to the device . <EOS>