Abstract: There is proposed a registration apparatus, a verification apparatus, and a program capable of improving authentication accuracy and an identification data structure capable of improving reliability. A blood vessel line included in an image is divided into a plurality of partial lines on the basis of end points and a diverging point of the blood vessel line. A parameter representing the shape of each of the partial lines is extracted on the basis of end points at both ends of the partial line. Data including points at both ends of each of the partial lines and the parameter is generated as data to be registered or data to be compared with registered data.