First of all it will add an additional logon method(right now only passcode exists). Second, it will be integrated into Passbook for purchasing. Third, Apple will allow you to use it for app store purchases and iTunes instead of your Apple password. Fourth, Apple will offer an enterprise service to online retailers and websites to use Apple Secure Logon. The way that will work is Apple keeps a database of fingerprint images with unique IDs(maybe a hash value of the print). Databases have long supported BLOB data and this is a perfect application of it. The way a 3rd party app uses Apple Secure Logon is like this: 1. When you register as a new user(or customer), the app presents the Fingerprint UI control. The control scans the image of your print, sends it back to Apple through a proprietary web service interface and gets back the hashcode. 2. The app uses that hashcode as your userid in it's private database. After that you have the option to enter your address/phone OR allow them to look it up from Apple's database through fingerprint logon. 3. Then later when you need to logon to an app, it presents you with the fingerprint control again, gets back the Apple hashcode, does the hashcode looup in it's own database and you're logged in.