Blockchain-Based Authorization Mechanism for Educational Social Internet of Things

The Social Internet of Things (SIoT) paradigm has been integrated in the education domain to enable educational IoT devices to establish social relationships and exchange academic services. Nonetheless, the social relationships are not adapted to the educational context where devices must be socially linked based on their academic roles and activities. Furthermore, the exchange of services raises the requirement to implement an access control mechanism. In SIoT, social constraints such as the social relationship type and contact frequency are critical requirements to make an access decision. However, these constraints cannot be specified using the eXtensible Access Control Markup Language (XACML) standard as device attributes nor as contextual conditions. In this paper, we propose an Educational Social Internet of Things (EducationalSIoT) platform implemented as an application-specific blockchain where we define new social relationships for educational devices. To control the access to the academic services, we suggest extending the XACML policy model by considering the social requirements, and accordingly, we adjust the policy evaluation process and suggest priority-based combining algorithms. Additionally, our platform ensures the delegation of access permission by defining delegation policies and controlling the delegation operation with consideration of the social features. The simulation results show that by integrating social features, an access request is evaluated in 0.22 ms and a delegation request is evaluated in 0.32 ms. Finally, we guarantee that our platform is protected against the man-in-the-middle and replay attacks.