Unlocking your iPhone

Doug Aamoth has a Time article about the new iPhone lock:

At launch, the Home button on the iPhone 5S can be used to unlock your phone without having to enter your PIN, and it can be used to authenticate iTunes purchases without requiring you to enter your password. It wouldn’t be surprising to see such functionality eventually extended to third-party apps as well.
This has lead to the inevitable assumption that thieves the world over will be roaming the streets with cigar cutters, looking to anyone flashing an iPhone 5S. The thieves will subdue you, chop your finger off, use it to unlock your phone, and then use it to purchase Herbie: Fully Loaded with your money. These thieves will preserve your severed finger for eternity, using it time and time again to download apps, movies, television shows, and songs until you finally go bankrupt.
You will call Apple first to see if you can “change your password,” at which point the rep on the other end will cackle: “Change your password? Your fingerprint is your password! You can’t change your fingerprint. Are you new here? Are you new to life?? This is your first day, isn’t it?!” *click*
Picture the same scenario, except instead of chopping your finger off, thieves do the old lift-your-fingerprint-from-a-glass trick and then manufacture a fake finger with your fingerprint on it, subdue you, steal your phone, and then download Herbie: Fully Loaded.
This is the future we’re about to enter, right? A bunch of people with missing fingers and stolen phones.
Except it’s apparently not going to work. The new breed of fingerprint sensors will require a live finger, according to Mary Branscombe over at CITEWorld. She writes:

Like the sensor in the iPhone 5S, the sensors that will be in laptops and keyboards and other phones can detect the ridge and valley pattern of your fingerprint, not from the layer of dead skin on the outside of your finger (which a fake finger can easily replicate), but from the living layer of skin under the surface of your finger, using an RF signal. That only works on a live finger; not one that’s been severed from your body.

This will protect you from thieves trying to chop off your finger when they mug you for your phone (assuming they’re tech-literate thieves, of course), as well as from people with fake fingers using the fingerprint they lifted from your phone screen.
This new breed of sensor is unlike the ones you may have used on previous laptops, for instance (or the Motorola Atrix, if you owned that smartphone). There’s no swiping involved this time around. Apple purchased fingerprint-sensor maker Authentec a while back, which used to make these swipe-style sensors, though Branscombe points out: “Ironically, Apple might have helped speed up the switch to the new style of fingerprint sensor in PCs by telling PC makers they could no longer buy the old fingerprint sensors from Authentec after it bought the company.”
Here’s hoping would be thieves get the memo that the tried and true fingerchop isn’t going to work. They’ll need to do things the old fashioned way: bully you into unlocking your phone and downloading Herbie: Fully Loaded for them.

Rico says why anyone would ever want to download Herbie: Fully Loaded, even if they were 'fully loaded', is beyond him...