Touch ID

I develop the App to authenticate using Touch ID.

I want to know what fingerprint is used to authenticate when many fingerprints enrolled in iPhone.

For example, I enrolled fingerprints (finger1, finger2, finger3) and process authentication.

In this case, I want to obtain unique fingerprint identifier like ID1, ID2, ID3.

But supporting Touch ID APIs just notice that authentication is successful or not.

How can I identify what fingerprint is used to authenticate?

Touch ID
 
 
Q