A method of verifying programming of an integrated circuit card includes transferring program data to a page buffer of a non-volatile memory, copying the program data to a buffer memory, calculating a first checksum value with respect to program data in the buffer memory, updating the program data in the buffer memory by copying the program data of the page buffer to the buffer memory, calculating a second checksum value with respect to updated program data in the buffer memory, comparing the first checksum value and the second checksum value, and determining, based on the comparison result, whether the program data of the page buffer is tampered.