According to an aspect of the invention, a management of each authentication subprocess assures the each authentication subprocess, and assurance contents can be verified by verification side, so that trustworthiness of the whole authentication process can be improved. An authentication system includes authentication entity devices (10, 20) which separately execute authentication subprocesses P1 and P2 and a verification device (30) which verifies the executed contents of each of the authentication subprocesses P1 and P2. The entity device includes a confidential information management unit(13, 23) which manages confidential information, an authenticator generating unit (14, 24) which generates an authenticator using the confidential information, and a context generating unit (15, 25) which generates a specific context pursuant to a specific format from the authenticator and the executed contents.