| 摘要 |
PROBLEM TO BE SOLVED: To appropriately make a decision whether an ink cartridge is a previously registered product or not. SOLUTION: An encrypting section 124 encrypts the serial number ID of an ink cartridge 200 using a first private key Ka to generate a bit matrix BM. A logical operating section 126 calculates XOR of first extra information A1 and the bit matrix BM to obtain a random number RND. The encrypting section 124 encrypts the random number RND using a second private key Kb to create a digital signature SIG'. The logical operating section 126 calculates XOR of second extra information A2 and the bit matrix BM to obtain a digital signature SIG. A comparing section 128 compares the digital signature SIG thus obtained with the generated digital signature SIG' and makes a decision that a mounted ink cartridge 200 is a registered product if the digital signatures SIG and SIG' coincide with each other otherwise makes a decision that the mounted ink cartridge is not a registered product. COPYRIGHT: (C)2004,JPO |
