ios - How do i store finger print against database record -

i using touch id , appears work fine pushing view in when sucesffull fingeer print found question how store against user record in azure can ups on customer data best way of doing this. ie should finger print reader o active once have signed app.

the following code using catch finger print on btn touch inside

partial void touchid(uibutton sender) {

    //lets double check device supports touch id     if (context.canevaluatepolicy(lapolicy.deviceownerauthenticationwithbiometrics, out error))     {         var replyhandler = new lacontextreplyhandler((success, error) =>             {                 invokeonmainthread(() =>                     {                         if (success)                         {                             var newvc = new uiviewcontroller();                       presentviewcontroller(newvc, true, null);                         }                         else                         {                             var alert = new uialertview("oops!", "something went wrong.", null, "oops", null);                             alert.show();                         }                     });             });         context.evaluatepolicy(lapolicy.deviceownerauthenticationwithbiometrics, "logging in touch id", replyhandler);     }     else     {         var alert = new uialertview("error", "touchid not available", null, "booo!", null);         alert.show();     } }