A template can be thought of as the refined and processed information about the distinguishing characteristics of a particular individual. In the case of fingerprints it MIGHT be the location and direction of the minutiae or for iris the position of the filaments around the eye center. The information in a template MUST be enough for the recognition algorithm to distinguish between one individual and every other individual the system might ever see (possibly everybody!).

So, while the system does not store all the details of a person (the full face or fingerprint image for instance), it must store enough data so that if you KNEW how the recognition algorithm operated you could reconstruct a likeness of that individual SUFFICIENT to be able to FOOL that system. This is one reason why it is important that templates are encrypted when they are stored.

A template can be thought of as the refined and processed information about the distinguishing characteristics of a particular individual. In the case of fingerprints it might be the location and direction of the minutiae or for iris the position of the filaments around the eye center. The information in a template must be enough for the recognition algorithm to distinguish between one individual and every other individual the system might ever see (possibly everybody!).

So, while the system does not store all the details of a person (the full face or fingerprint image for instance), it must store enough data so that if you knew how the recognition algorithm operated you could reconstruct a likeness of that individual sufficient to be able to fool that system. This is one reason why it is important that templates are encrypted when they are stored.