Fiscal Printer
AssigneeSeiko Epson Corporation
InventorsTamakazu Kitamura, Hiroshi Yabe
Life of this patent
Estimating the term…
Abstract
Tampering with fiscal information written to memory can be detected without reducing the write speed. When fiscal information is written to first memory unit 411 by means of a fiscal control CPU 42 , a memory control CPU 412 writes a first hash value corresponding to the fiscal information in second memory unit 413. When fiscal information is read from the first memory unit 411, the fiscal control CPU 42 reads the first hash value from the second memory unit 413 through the memory control CPU 412, compares the first hash value with a second hash value calculated from the fiscal information read from first memory unit 411, and detects tampering with the fiscal information.
Claims8
A fiscal printer comprising:
- a nonvolatile first memory unit in which fiscal information is written and read;
- a second memory unit in which a first hash value, which is calculated for the fiscal information using a specific hash function, is written and read when the fiscal information is written to the first memory unit;
- and
- a tampering detection unit that, when the fiscal information is read from the first memory unit, determines if the fiscal information read from the first memory unit was tampered with based on the first hash value read from the second memory unit, and a second hash value that is calculated using the hash function for the fiscal information read from the first memory unit.
Dependencies are inferred from the claim text.