Patent ID: 7202960
Filing Date: 2007-04-10
Classification: H04N

Abstract:
1. A print sheet original authentication system comprising: a print data creation portion for creating print data having an electronic mark added to the original data; a printer device for printing the print data on a print sheet as a print pattern; and a checking device for checking for the mark on the print sheet; wherein: (a) the printer device comprises: a print sheet reading sensor for reading the print pattern on a print sheet on which printing has been carried out; a remaining mark amount detection portion for detecting the remaining mark amount from a print pattern of a read print sheet; a generation control information creation portion for converting the remaining mark amount to generation control information; a printing portion for printing the generation control information on the print sheet; a cryptographic key creation portion for creating a cryptographic key used for encrypting the generation control information; a generation control information encrypting portion for encrypting the generation control information using the cryptographic key; and a cryptographic key output end for outputting the cryptographic key to the checking device; and (b) the checking device comprises: a print sheet reading sensor for reading the print pattern of the input print sheet; a mark information checking portion for detecting the mark information on the print pattern of the read print sheet, checking the electronic mark and calculating the remaining mark amount; generation control information detection portion for detecting the generation control information of the print pattern of the read print sheet, and extracting the remaining mark amount from said generation control information; a remaining mark amount comparison portion for comparing the calculated remaining mark amount obtained by mark detection with the remaining mark amount extracted from the generation control information; a cryptographic key input end which inputs the cryptographic key; and a generation control information decrypting portion which decrypts the encrypted generation control information.