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. Coefficients of terms corresponding to degrees included in a polynomial equation for an n-th order curve representing each of the partial lines are extracted. Data including points at both ends of each of the partial lines and the coefficients is generated.