| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a printing system with a time stamp having a tampering prevention function for easily proving authenticity of electronic data of a printed matter printed and issued, preventing unauthorized use of a time stamp printed on the printed matter to surely prevent tampering and unauthorized use of the printed matter, and accurately verifying authenticity of a document printed and issued. <P>SOLUTION: When printing and issuing a document YA, the system prints and issues, at the same time, a time stamp Y3 generated at a normal time, a two-dimensional code Y1 obtained by converting printed print data to a two-dimensional code, and a two-dimensional code Y2 obtained by encoding information including a uni-directional function value calculated based on the printed print data and information used by a third institution for determining authenticity and converting the encoded information to a dimensional code. <P>COPYRIGHT: (C)2004,JPO |
