A system configured to perform decision tasks carried out by a machine learning engine operates with a machine learning model, and includes a training component for improving the machine learning model, a device for carrying out decisions based on a set of input data, and an interaction interface for switching the machine learning model between training component and a device that includes a model attestation checker. The device performs acquiring input data, and ascertaining at least one machine learning model over the interaction interface. The model attestation checker performs checking if said machine learning model is trusted by a model attestation, and considering, for decision making, only those machine learning models that are trusted. The machine learning engine performs carrying out the decision task for input data by using a trusted machine learning model, and providing a result attestation for the decision output.