Association: Unobtrusively Creating Digital Contracts with Smart Products

Many business models for smart products, like pay-per-use, require that the smart product can digitally verify whether the user has a contract with the smart product and should be granted access to privileged functionality. Traditional means to do so, e.g. password login, are very obtrusive and can thus not be applied for smart product scenarios. In this paper, we present the mechanism of association. Associations represent the abstract concept of a digitally checkable contract on the middleware level. Associations use a service for digitally representing the user that performs the tedious parts of creating a digitally checkable contract automatically. Thus, the interaction can be established unobtrusively. As this service acts on behalf of the user, the user must trust this service. We address this issue in two ways: the service is executed on the personal trusted device of the user and the user can control and inspect the actions of the service via a user interface.