FIELD: information technologies.
SUBSTANCE: method for data modification in system for settlement of transactions using cards includes smart card and readout device performed with possibility to read card. This card comprises non volatile, erasable and rewritable memory containing at least two cells for writing data value connected with transactions performed via the said card. Each transaction causes modification of the said data value and the latter is monotone function in time. In each transaction data value writing operation provides writing new data value (Y) in the first cell (B) of two cells in memory which cells form counter. In this process this writing operation provides old data value erasing from the second cell (A), so that at the end of correctly performed operation the first cell contains new data value and the second cell contains zero.
EFFECT: guarantee of data integrity maintenance ensured by providing data modification in smart card during transaction performed in minimal time period compatible with access time.
8 cl, 7 dwg
