研究成果

In this paper, as a fundamental cryptographic protocol with information-theoretic security, we propose unconditionally secure blind authentication codes in the manual channel model. The blind authentication code is a protocol in which a user can obtain a signer's authenticator of a message with anonymity of a message and a verifier can verify the validity of it. To realize such a mechanism, it is known that each entity of the system, a user, a signer, and a verifier needs to have secret information. In our model of blind authentication codes in the manual channel model, a verifier can verify the validity of an authenticated message without any secret key. In this paper we propose a formal model and security formalization of blind authentication codes in the manual channel model. In addition, we present a construction of unconditionally secure blind authentication codes in the manual channel model.