CERTIFICATE VALIDATION METHOD AND CERTIFICATE VALIDATION SERVER AND STORAGE MEDIUM

A certificate validation method for causing a certificate validation server to receive a certificate validation request from a given terminal device, build a certification path of from a first certificate authority (CA) to a second CA, perform validation of the certification path, and send a validation result to the terminal which issued the certificate validation request is disclosed. The validation server detects either a key update of any given CA or a compromise of the given CA, acquires a certificate of relevant CA and first certificate status information and second certificate status information, stores the acquired information in a storage unit or, alternatively, updates the information stored in the storage based on the acquired information, and performs the building of a certification path and validation of the certification path by use of the information of the storage unit.