Multi-authority Decentralized Attribute-Based Authorization Framework

The advancement in collaborative work among multiple institutions results in tremendous data sharing and, at the same time raises concerns about data security and privacy. Current systems are mostly built upon a centralized model, so the system requires one authority to concede another authority or mitigate trust to a trusted third party.

In this paper, we propose a multi-authority decentralized attribute-based authorization framework illustrated in an eHealth scenario that provides resilience and transparency, enforces data privacy, and allows each authority to enforce their access policy on the shared data. The framework operates on Blockchain technology and multi-authority attribute-based encryption. Our framework protects against malicious single authority who aims to grant permission to users to the shared data. Moreover, we optimize the user key structure that could reduce the key size of the key set by a factor of up to n! where n is the number of attributes in the user key to eliminate brute-force attacks. We implement the framework, show the system performance, and prove the efficiency of our proposed framework.