Secret key registration method, secret key register, secret key issuing method, cryptographic communication method and cryptographic communication system

摘要

At each entity, a plurality of passwords based on a basic password and one-way functions are generated and sent to the respective key issuing agencies (respective centers). These passwords are used by each entity to receive in a secured manner the secret keys of each entity issued by the respective key issuing agencies (respective centers). The number of passwords that need to be managed at each entity is decreased. The secret keys are readily issued in a secured manner for each entity by a plurality of key issuing agencies (centers).