Bitcoin is the first decentralized global currency cryptosystem and a complete digital money that has increased in value and popularity since 2009. It is a collection of cryptographic protocols that allows secure online transactions between users and is based on a peer-to-peer network powered by its users. In this study, we investigate the use of Bitcoin and its underlying technologies as a platform for innovative systems. In particular, we use Bitcoin as an infrastructure to realize a trans-organizational role-based access control (RBAC) system and an electronic-voting (e-voting) system.
The RBAC is a natural and versatile model of the access control principle. In the real world, it is common that an organization provides a service to a user who owns a certain role that was issued by a different organization. However, such a trans-organizational RBAC is not common in a computer network because it is difficult to establish both the security that prohibits malicious impersonation of roles and the flexibility that allows small organizations and individual users to fully control their own roles. Therefore, we propose a trans-organizational RBAC mechanism that makes use of Bitcoin to represent the trust and endorsement relationship that are essential in RBAC and a challenge-response authentication protocol that verifies a user's ownership of roles.
E-voting is a promising platform that aims to provide a secure, convenient, and efficient voting environment over the Internet. Various cryptographic schemes have been studied to realize secure and efficient e-voting systems, but these systems are hardly used in practical voting. One of the technical reasons for this unfortunate situation is that many e-voting systems require an anonymous communication channel, which is difficult to implement over the Internet. Therefore, we propose the use of Bitcoin and complement with known protocols, such as the blind signature protocol and digital signature protocol, to realize an e-voting system that is secure, anonymous, and transparent. We discuss several important properties of e-voting systems, including fairness, eligibility, anonymity, robustness, and verifiability, and shows that the use of the Bitcoin protocol brings favorable features besides the anonymity of the communication.