There has been lots of speculation that the iPhone 5 was Steve Jobs’ last major project at Apple. That has always felt pretty shallow. The iPhone 5 was a significant redesign, but certainly not the groundbreaking kind of release that would consume a visionary’s thoughts.

This answer on Quora has me wondering if it was actually Touch ID. He certainly had to be aware of the project if it was in-progress while he was at Apple. The vision necessary to see something like that as far back as 2008 is very much in the realm of Steve.

Apple has taken a very slow and methodical approach with the release of Touch ID.  We can see that there was a tremendous amount of amazing work that has gone into this project.  All of this convergence took over seven years of very hard work. It includes many patent applications, the acquisition of AuthenTec, the selection of the A7 processor and the integration of the TrustZone suite all baked together into what we now know as Touch ID.
Sounds about like Steve to me.

Via Daring Fireball