An information processing apparatus inputs image data including a first pixel group, a second pixel group generated by interpolating the first pixel group and verification data of the first pixel group, verifies whether the first pixel group has been altered using the first pixel group and the verification data, verifies whether the second pixel group has been altered by determining whether the second pixel group and the first pixel group are in a predetermined relationship, and determines whether the image data has been altered based on results of the verification as to whether the first pixel group has been altered and the verification as to whether the second pixel group has been altered.