[youtube http://www.youtube.com/watch?v=EuEovgmVCUs?enablejsapi=1&autoplay=0&%23038;cc_load_policy=0&%23038;iv_load_policy=1&%23038;loop=0&%23038;modestbranding=0&%23038;rel=1&%23038;showinfo=1&%23038;playsinline=0&%23038;autohide=2&%23038;theme=dark&%23038;color=red&%23038;wmode=opaque&%23038;vq=&%23038;controls=2&%23038;&w=480&h=388]
OAuth2 is a popular authentication protocol used by sites like Facebook and this tutorial explains how to implement it in Object Pascal using Delphi Firemonkey.
StackOverflow: Firemonkey
Embarcadero: Firemonkey OOP
Embarcadero: Firemonkey C++