To provide a system for authentication and management which absolutely does not invert the order of the operation of transmission/reception and transmission/reception events occurrence time, needs neither a timer on the access side nor standard time such as UTC (universal time coordinated), and can supply the synchronous time for the countless access computers in multiple communication processes between the access computers in the computer network environment connected by communication lines and the accessed computer receiving the communication access.

The transmission/reception on the access side and the accessed side in the communication process, and the order of occurrence of the transmission/reception events are recorded at tentative time whose irreversibility is established logically. It is stored and updated as the authentication data related to the access computer of the party in communication. The authentication data is used mutually. The authentication data is used as the authentication data of the access computer on the accessed side, moreover as the authentication data of the accessed side computer on the access side.