Cryptographically Enforced Access Control in Blockchain-Based Platforms

In this paper, we took a two-stage approach to address privacy issues in blockchain-based applications. Using smart contracts, our approach automatically enforces access policies through encryption and is in contrast to most access control models that solely rely on smart contract policies. These contracts are prone to many security vulnerabilities and in some cases written by developers whose trustworthiness is dubious. A cryptically enforced access control, on the other hand, gives more of the sovereignty promised by the blockchain technology, back to users as showcased in our medical data management framework.