Blockchain Based Access Control Services

This paper presents a new design approach for Access Control services leveraging smart contracts provided by blockchain technology. The key idea of our proposal is to codify Access Control policies as executable smart contracts on a blockchain. This transforms the policy evaluation process into completely distributed smart contract executions. In our fully blockchain based approach also the Attribute Managers required for the evaluation of the Access Control policies are managed by the blockchain, i.e., they are implemented as smart contracts as well. To study the feasibility of our proposal we present a working reference implementation using XACML policies and Solidity written smart contracts deployed on Ethereum. Finally we evaluate the advantages and drawbacks of the proposal, making also use of experimental results of our reference implementation.