Touch ID on the iPhone and iPad is such a handy and convenient security feature that would be a welcome addition to the Mac. But how would you implement it? Add a Touch ID hardware sensor to the keyboard? Seems like an odd fit for Apple design-wise.
According to MacRumors, Apple may have found a way: by allowing Touch ID on an iPhone unlock a Mac. The iPhone would use Bluetooth LE to connect to a Mac, and using Touch ID would work in place of entering a password. (An app called Knock already does something similar, letting you unlock your Mac with your iPhone or even your Apple Watch.) MacRumors also said that the Touch ID implementation would also work with the rumored Apple Pay for web browsers, where you can use Apple Pay for online purchases.