COIChain: Blockchain scheme for privacy data authentication in cross-organizational identification

In cross-institutional user authentication, users’ personal privacy information is often exposed to the risk of disclosure and abuse. Users should have the right to decide on their own data, and others should not be able to use user data without users’ permission. In this study, we adopted a user-centered framework, so that users can obtain authorization among different resource owners through qualification proof, avoiding the dissemination of users’ personal privacy data. We have developed a blockchain-based cross-institutional authorization architecture where users can obtain identity authentication between different entities by structuring transactions. Through the selective disclosure algorithm, the user’s private information is hidden during the user identity authentication, and the authenticity of the user’s private information is verified by disclosing the user’s non-private information and authentication credentials. The architecture supports the generation of identity credentials of constant size based on atomic properties. We prototype the system on Ethereum. The prototype of the system is tested. The experiment proves that the sum of user information processing and verification time is about 80ms, and the time fluctuation of user information processing is very small. The results show that our data flow scheme can effectively avoid the privacy leakage problem in the user cross-agency authentication scenario with a small cost.