Geppy Parziale is an electronic engineer and a senior iOS and OS X engineer consultant for Apple, shares his view on Apple’s rumored use of a fingerprinting sensor in the next-generation iPhone.
According to Geppy Parziale, Apple will find it difficult to provide a great user experience if they attempt to use the fingerprint sensor for mobile payments.
Here are the key highlights from Geppy Parziale’s excellent report:
1) Identification and verification
Identification or 1-to-many recognition is used to compare a fingerprint against a (large) set of fingerprints. This is usually used, for example, when you enter the United States: you provide your 10 fingerprints and the system compares them against all the fingerprints contained in a database of criminals or wanted people (the so-called black list). This is done with an Automated Fingerprint Identification System or, AFIS.
Verification or 1-to-1 recognition is used to check if you are really who you claim to be when you try to access a system or a device. Verification will be used in the iPhone. This is important to know, because verification is much easier to perform than identification and allows less constraint during the recognition and the use of lower quality fingerprint sensors.
Verification requires a reference fingerprint (the so called, template) that you have to provide the first time you use the system or device. Then, every time you try to access that same system or device, you will need to provide the same fingerprint to be compared against the template. If the system or the algorithm recognizes that the 2 fingerprints come from the same person, access will be granted, otherwise you will be rejected.
As with any other verification system, the iPhone will have an enrolling phase. As Apple knows how, this phase can be completely seamless for the user. Like Siri, the new fingerprint technology should be able to learn your fingerprints from the first moment you touch the device.
2) Fingerprint Sensors
Let’s take a look at the most critical component of the entire fingerprint recognition process: the sensor. Recognition is highly dependent on the quality of the captured fingerprint image as in less noise, and better image. The core technology used to manufacture the sensors can introduce noise and errors on the captured fingerprint image, influencing the recognition to such a negative extreme that you could be continually rejected by the system (false rejection) or somebody else could be granted access to the system instead of you (false acceptance).
Geppy Parziale concludes:
Unfortunately there is no existing solution to this. Manufacturers can only try to make the fingerprint sensor last longer, but sooner or later that device will stop working properly. This is also why Apple cannot provide a fingerprint sensor for payments. And if they do, they are making a huge mistake, because the surface destruction process explained above introduces the most dangerous problem in fingerprint recognition: false acceptance, when after a while somebody else can be granted access to your device.
…For you, this means that a fingerprint sensor on your phone will break after a while. How long after you buy it? Well, that will depend on where you live, how you use it, where you use it, how careful you are with it, and how clean your hands are.