Data transmission and reception system with accurate time information

摘要

A data transmission and reception system for exchanging data such as e-mail by using accurate time information over a network. An authorizing office authorizes an authorization mail server to issue electronic postmarks including highly accurate time information. Then, the authorization mail server stamps an electronic postmark with the highly accurate time information embedded in it on e-mail being sent by a sender. Here, the electronic postmark data, to which the time information has been attached in the authorization mail server, is made tamperproof by a predetermined electronic postmark issue program and further encrypted to be transferred to a receiver mail server.