Patent ID: 7721113

Claim:
A data alteration detection method for detecting whether any data record of a database is altered, comprising: calculating a data alteration detection code of data to write current time when writing data in a data storage unit in a prescribed order; calculating an inter-data record alteration detection code based on a data alteration detection code of at least immediately previous data record of the data record to write current time and a data alteration detection code of the data record to write current time; relating to each other and storing the data to write current time, the data alteration detection code and the inter-data alteration detection code in the data storage unit; calculating a data alteration detection code of the data to read when reading the data stored in the data storage unit, and verifying whether the calculated data alteration detection code coincides with the data alteration detection code stored in correspondence with the data to read; calculating an inter-data alteration detection code based on the data alteration detection code of the data to read and the data alteration detection code of at least the immediately previous data record; and verifying whether the calculated inter-data alteration detection code coincides with the inter-data alteration detection code stored in correspondence with the data to read.