Since the Information Model for an AutomationComponent in a Descriptor is modelled as an AML InternalElement within an AML InstanceHierarchy or an AML SystemUnitClass, the tools that work directly with the Information Model shall support the use of AML constructs and the OPC UA FX AML Libraries.

Engineering tools should support the import or export of a Descriptor.

Any tool that exports a Descriptor shall require that the Descriptor be digitally signed at the end of the export cycle. The use of X.509 certificate technology is required to ensure the ability to authenticate the signature for further use by other tools. To create the digital signature, the tool shall allow the user to select an X.509 certificate, which can be either self-signed or CA-signed and taken from a file or a certificate store. The tool is required to check the validity of the certificate or certificates.

A tool that allows importing a Descriptor shall validate all digital signatures included in the Descriptor and ask the tool user to trust the certificates used for signing if the signing certificate is not already trusted by the tool. The user is not required to accept this trust and can block the import action.

When a signature cannot be fully validated or if no signature is present, and the tool is operating without a user interface, the import shall fail, and the tool should generate a log message.

When a signature cannot be fully validated or if no signature is present, and the tool operates with a user interface, meaningful warnings and error messages shall be displayed, and the tool should generate a log message. The import shall fail unless the user overrides the validation failure.