An entity device among a plurality of entity devices, used for an authentication system comprising an authentication apparatus capable of verifying a plurality of authentication contexts each including a processing result of a plurality of authentication subprocesses making up a biometric authentication process, a client apparatus capable of transmitting said each authentication context to the authentication apparatus, and a plurality of entity devices (30, 50) capable of individually generating and transmitting said each authentication context to the client apparatus, the entity device characterized by comprising: a confidential information storage device configured to store confidential information for verification by the authentication apparatus; a plurality of authentication subprocess execution devices (56, 57) having different performances and capable of generating a processing result by executing the same authentication subprocess; an entity certificate storage device configured to store an entity device certificate including execution device performance information and identification information on said each authentication subprocess execution device; an identification information storage device configured to store the identification information and a parameter related to each other for each authentication subprocess execution device; an execution device switching device configured to execute, upon receipt of a processing request and a parameter from the client apparatus, the authentication subprocess by accessing the identification information storage device and switching to the authentication subprocess execution device corresponding to the parameter; an authenticator generating device configured to generate an authenticator based on the confidential information in the confidential information storage device from the entity device certificate, the processing result of the authentication subprocess and the identification information indicating the authentication subprocess execution device that has executed the authentication subprocess; an authentication context generating device configured to generate an authentication context including the authenticator, the identification information used for generating the authenticator, the processing result and the entity device certificate; and an authentication context transmission device configured to transmit the authentication context to the client apparatus, wherein the authentication context transmitted by the authentication context transmission device is such that the authentication apparatus is capable of verifying the authenticator based on the confidential information identical with or corresponding to the aforementioned confidential information, the corresponding execution device performance information in the entity device certificate is extracted based on the identification information used for generating the authenticator, and the execution device performance information is capable of being verified based on predetermined performance criteria information. a confidential information storage device configured to store confidential information for verification by the authentication apparatus; a plurality of authentication subprocess execution devices (56, 57) having different performances and capable of generating a processing result by executing the same authentication subprocess; an entity certificate storage device configured to store an entity device certificate including execution device performance information and identification information on said each authentication subprocess execution device; an identification information storage device configured to store the identification information and a parameter related to each other for each authentication subprocess execution device; an execution device switching device configured to execute, upon receipt of a processing request and a parameter from the client apparatus, the authentication subprocess by accessing the identification information storage device and switching to the authentication subprocess execution device corresponding to the parameter; an authenticator generating device configured to generate an authenticator based on the confidential information in the confidential information storage device from the entity device certificate, the processing result of the authentication subprocess and the identification information indicating the authentication subprocess execution device that has executed the authentication subprocess; an authentication context generating device configured to generate an authentication context including the authenticator, the identification information used for generating the authenticator, the processing result and the entity device certificate; and an authentication context transmission device configured to transmit the authentication context to the client apparatus, wherein the authentication context transmitted by the authentication context transmission device is such that the authentication apparatus is capable of verifying the authenticator based on the confidential information identical with or corresponding to the aforementioned confidential information, the corresponding execution device performance information in the entity device certificate is extracted based on the identification information used for generating the authenticator, and the execution device performance information is capable of being verified based on predetermined performance criteria information.