Adapting Identity-based Encryption with Wildcards to Access Control

Nowadays, connected objects play an important role in our daily lives, providing services related to our cities, cars, homes, and health. For this purpose, they often need to be accessible by external entities, such as a garage owner (for a connected car), a postman (for a connected home), or a doctor (for a connected health device). However, it is crucial for the owner of such objects to retain control over their devices. One possibility is for the owner to define and manage access policies for their resources. In this presentation, we consider and present the use case where all the resources from connected objects are centralized on a Central Server. An owner can grant a requester access to a specific connected object based on an access policy defined by the owner and managed by an Authorization Server. Based on this use case, we enhance the Identity-Based Encryption with Wildcards primitive for access control. Specifically, we replace the key generation algorithm in the primitive with an interactive protocol involving three entities (the user, Central Server, and Authorization Server), resulting in a new cryptographic primitive that protects the privacy of both the requester and the owner. To demonstrate that this extended security still leads to practical schemes, we present the results of an implementation of our new primitive using Relic and different elliptic curves.