Abstract: Provided is a terminal authentication system including a client terminal and a server device. The client terminal transmits first information based on secret information different for each client terminal and a client certificate including a hash value of the secret information which is derived from the secret information, to a server device. The server device receives the first information and the client certificate, derives a hash value from the secret information based on the first information using a unidirectional function, and authenticates the client terminal on the basis of the derived hash value and the hash value of the secret information which is included in the client certificate.

Abstract: Provided is a signature verification system including a communication device and a verification device. The communication device and the verification device are connected to each other through a network. The communication device derives a first hash value from a first random number, derives a second hash value from data including electronic data and a certificate of the communication device which includes the first hash value and a public key of the communication device, using a unidirectional function, generates a signature using a secret key of the communication device with respect to the second hash value, and transmits the electronic data, the certificate, and the signature to the verification device.

Abstract: Provided is a certificate issuing system including a client terminal and a server device. The client terminal derives a first hash value from a first random number using a unidirectional function, generates a secret key and a public key of the client terminal, and transmits the first hash value and the public key of the client terminal to the server device. The server device receives the first hash value and the public key of the client terminal from the client terminal, stores the first hash value, authenticates the client terminal on the basis of the stored first hash value and the derived first hash value, generates a client certificate on the basis of the public key of the client terminal and a secret key of the server device when the authentication succeeds, and transmits the client certificate to the client terminal.

Abstract: Provided is a signature verification system including a communication device and a verification device. The communication device and the verification device are connected to each other through a network. The communication device derives a first hash value from a first random number, derives a second hash value from data including electronic data and a certificate of the communication device which includes the first hash value and a public key of the communication device, using a unidirectional function, generates a signature using a secret key of the communication device with respect to the second hash value, and transmits the electronic data, the certificate, and the signature to the verification device.

Abstract: Provided is a terminal authentication system including a client terminal and a server device. The client terminal transmits first information based on secret information different for each client terminal and a client certificate including a hash value of the secret information which is derived from the secret information, to a server device. The server device receives the first information and the client certificate, derives a hash value from the secret information based on the first information using a unidirectional function, and authenticates the client terminal on the basis of the derived hash value and the hash value of the secret information which is included in the client certificate.

Abstract: Provided is a certificate issuing system including a client terminal and a server device. The client terminal derives a first hash value from a first random number using a unidirectional function, generates a secret key and a public key of the client terminal, and transmits the first hash value and the public key of the client terminal to the server device. The server device receives the first hash value and the public key of the client terminal from the client terminal, stores the first hash value, authenticates the client terminal on the basis of the stored first hash value and the derived first hash value, generates a client certificate on the basis of the public key of the client terminal and a secret key of the server device when the authentication succeeds, and transmits the client certificate to the client terminal.

Abstract: The present invention has as an object thereof to provide a logical operational circuit which is capable of realizing, with present semiconductor manufacturing technology, logical functions, the realization of which has been extremely difficult heretofore as a result of constraints in the voltage levels which are to be discriminated on the floating gate of the neuMOS.