Policy-Driven Blockchain and Its Applications for Transport Systems

Blockchains offer opportunities for developing advanced digital services. While current research on this topic is still growing, various security concerns have been raised and the security of blockchains has been becoming the most important issue which must be well addressed. Blockchain transactions are based on digital signatures, where the public key is associated with the ownership of the digital coin. User management of public or permissionless blockchain is ad hoc, i.e., any user can join and leave the blockchain network and participate in the Proof of Work (PoW). However, in a private blockchain and a permissioned blockchain, there are usually some constraints for users. In this paper, we investigate a scenario which provides a blockchain network with a set of policies where every user's signing key is associated with a policy set. It is particularly interesting while users are working in different sectors. We call our scheme as "policy-driven", since policies in our scheme restrict users' rights. Our system is featured with a novel and lightweight policy-driven signature (PDS) scheme whose security has been proven formally. To justify our scenario, we provide experimental results and an example for the railway management services.