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Touch ID Patent Applications Show Details Behind 'Secure Enclave' and iPhone 5s Implementation

A pair of patent applications related to Apple's new flagship iPhone feature Touch ID shed some new light on how the fingerprint sensor itself works, as well as the "Secure Enclave" inside the A7 processor that analyzes and stores user fingerprints.

The first, as noticed by Patently Apple, details a method by which the iPhone scans a finger and then provides that data to the "Secure Enclave" for matching and eventual approval.

Rather than storing actual images of fingerprints, Apple takes a fingerprint map and runs it through a sort of encryption to prevent thieves from pulling fingerprint data from a compromised iPhone. The enclave only allows fingerprints to be checked against known valid ones, not the other way around.

Secureenclave
From Patently Apple
:
Apple's invention includes a process of collapsing the full [finger] maps into a sort of checksum, hash function, or histogram. For example, each encrypted ridge map template can have some lower resolution pattern computed and associated with the ridge map. One exemplary pattern could be a histogram of, e.g., the most common angles (e.g., a 2 dimensional (2D) array of common angles). The exemplary pattern could include in each slot an average value over a respective vector of the map. The exemplary pattern could include in each slot a sum of the values over a respective vector of the map. The exemplary pattern could include the smallest or largest value within a respective vector of the map, or could be a difference between a largest and a smallest value within the respective vector of the map.
One interesting note about the secure enclave patent is the main inventor, Wayne Westerman. He was one of the lead inventors on the multi-touch technology that Apple eventually purchased and uses as the key feature in Apple's billion-dollar iPhone and iPad lines. Westerman has been a senior engineer at Apple since his company, Fingerworks, was purchased by Apple in 2005.

In a separate application, Apple lays out the different parts that make up the Touch ID fingerprint sensor, including the different bits that Apple shows off in its marketing materials (shown below). Bottom image courtesy Patently Apple.

Touchid
AppleInsider notes that the patent addresses the opaque home button that nonetheless scans fingerprints:
Touch ID's aesthetic treatments have been included as well, as the patent details "an ink assembly...printed on the lens" that "has the effect that the otherwise-translucent button can be made opaque, so the elements of the fingerprint recognition sensor are not immediately visible to the user."
Neither patent has yet been awarded, with the applications initially filed in March. Provisional applications were filed back in May of 2012, illustrating how long the technology has been in development.

Top Rated Comments

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12 months ago

Haters hate but I'm still bummed that they didn't add the tech to the new iPads. :(


With the reports of low yields for the sensors prior to the 5s launch I wasn't suprised.
Rating: 7 Votes
12 months ago
Haters hate but I'm still bummed that they didn't add the tech to the new iPads. :(
Rating: 6 Votes
12 months ago
Wow, thats sophisticated.
Rating: 5 Votes
12 months ago
How long before samedung shamefully steals, copies, and claims as their own this invention?
Rating: 5 Votes
12 months ago
"Can't innovate anymore, my ass!"

Those who know less about something tend to think they know it all. They underestimate the complexity and think things can't possibly be this complicated. Yup, this is on the same level as the Motorola Atrix sensor :rolleyes:
Rating: 4 Votes
12 months ago

How long before samedung shamefully steals, copies, and claims as their own this invention?


Or maybe they'll just include a powerful enough secure processor, that such a helper hack is not necessary.

--

Btw, it's really childish when people make up nicknames for companies. It's like putting a giant immaturity mark on your post. Hard to take anyone's opinion seriously after that.

Reminds me of when people used to call Apple "Crapple", or use "M$" for Microsoft, or use "Commode-Door" for Commodore.
Rating: 3 Votes
12 months ago

How long before samedung shamefully steals, copies, and claims as their own this invention?


I personally hope they screw it up in the fashion of the HTC One Max's sensor. Man, that thing sucks.
Rating: 3 Votes
12 months ago

The enclave only allows fingerprints to be checked against known valid ones, not the other way around.


Can someone explain to me how it could be "the other way around", unless Touch ID knew the billions of fingerprints that belong to other people?
Rating: 2 Votes
12 months ago
Now, get enough supplies and put it in next years' Macs and iPads ;)
Rating: 2 Votes
12 months ago
The idea is to speed up fingerprint recognition by using the main processor, without giving up security.

The Secure Enclave Processor (SEP) reduces the fingerprint patterns to non-identifiable data, that can then be searched/matched by the much more powerful main Application Processor (AP) without compromising security.

The AP then hands back the short list of POTENTIAL matches to the SEP, which only has to do a detailed match of the secure data it has, against that short list.

Of course, this division of labor makes more sense if you're matching lots of fingers. Or if the SEP is really slow in comparison to the AP.
Rating: 2 Votes

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