Touch ID and A7 Secure Enclave Detailed in Updated Apple Security Document

Apple today posted an updated security document [PDF] on its iPhone in Business site, offering details on the inner workings of both Touch ID and the "Secure Enclave" built into Apple's A7 processor (via TechCrunch).

Since its 2013 release, Touch ID has faced scrutiny over privacy concerns from both users and government officials, and while Apple has previously offered few details on how Secure Enclave works, it has assured users that the system stores only fingerprint data rather than images.

touchid
According to the updated security document, Secure Enclave is a coprocessor within the A7 chip that uses a secure boot process to ensure that its separate software is both verified and signed by Apple. All Secure Enclaves can function independently even if a kernel is compromised and each one contains a unique ID inaccessible to other parts of the system and unknown to Apple, preventing the company or any other third parties from accessing data contained within.

Each Secure Enclave is provisioned during fabrication with its own UID (Unique ID) that is not accessible to other parts of the system and is not known to Apple. When the device starts up, an ephemeral key is created, tangled with its UID, and used to encrypt the Secure Enclave's portion of the device's memory space.

Additionally, data that is saved to the file system by the Secure Enclave is encrypted with a key tangled with the UID and an anti-replay counter.

Fingerprint data collected from Touch ID is stored within the Secure Enclave, which is used to determine a match and then enable a purchase. While the A7 processor collects data from the Touch ID sensor, it is unable to read it because it is encrypted and authenticated with a session key built into Touch ID and the Secure Enclave.

It's encrypted and authenticated with a session key that is negotiated using the device's shared key that is built into the Touch ID sensor and the Secure Enclave. The session key exchange uses AES key wrap- ping with both sides providing a random key that establishes the session key and uses AES-CCM transport encryption.

Along with details on the function and security of the Secure Enclave, the document contains details on Touch ID, most of which have been previously published by Apple in other documents and literature on the feature. It also offers some specifics on the security of fingerprint capturing and a reminder that fingerprint data is accessible only to the Secure Enclave and never sent to Apple or backed up to iTunes or iCloud.

The document's section on Touch ID and the Secure Enclave ends with a detailed description of how both Secure Enclave and Touch ID work together to unlock an iPhone 5s, which is well worth a read for users interested in how the technology functions.

Apple's updated security document has been added as part of a larger redesign of the IT section of its iPhone in Business site, which now features a cleaner design with navigation icons at the top of the page.

Top Rated Comments

Klae17 Avatar
99 months ago
Good timing with the new Samsung S5 Touch-wipe-button. Hey how come no one cares about security when Samsung does it yet when Apple does it we all FLIP?
Score: 34 Votes (Like | Disagree)
taptic Avatar
99 months ago
And the new Galaxy S5, in cooperation with Android, immediately sends your fingerprint to Google headquarters! No hassle guaranteed!
Score: 23 Votes (Like | Disagree)
Nunyabinez Avatar
99 months ago
I would have preferred that they called it the "Fortress of Solitude" rather than the "Secure Enclave."
Score: 20 Votes (Like | Disagree)
DaveN Avatar
99 months ago
Because you're on an Apple-based website?

I posted a question concerning obvious Android fanaticism on the Android Police site some months ago. The amount of hate posts received in response to what was a simple and honest question was astounding. Bottom line is that Apple Fanbois are much more civilized and even tempered than are Fandroids, IMHO.
Score: 12 Votes (Like | Disagree)
seamer Avatar
99 months ago
Good timing with the new Samsung S5 Touch-wipe-button. Hey how come no one cares about security when Samsung does it yet when Apple does it we all FLIP?

Samsung will fix it when Apple shows them how.
Score: 11 Votes (Like | Disagree)
\-V-/ Avatar
99 months ago
Good timing with the new Samsung S5 Touch-wipe-button. Hey how come no one cares about security when Samsung does it yet when Apple does it we all FLIP?
Because you're on an Apple-based website?
Score: 11 Votes (Like | Disagree)

Top Stories

apple california streaming event

Apple Event Announced: 'California Streaming' on September 14 With iPhone 13, Apple Watch Series 7 Expected

Tuesday September 7, 2021 9:03 am PDT by
Apple today announced that it will be holding a special event on Tuesday, September 14 at 10:00 a.m. The event will take place at the Steve Jobs Theater on the Apple Park campus in Cupertino, California. As with WWDC and last year's fall events, this new event will be held digitally with no members of the media invited to attend in person. Apple will likely provide pre-taped segments for...
iphone 12 colors 2021

iPhone 12 Colors: Deciding on The Right Color

Thursday November 5, 2020 8:35 am PST by
The iPhone 12 and iPhone 12 Pro arrived in October 2020 in a range of color options, with entirely new hues available on both devices, as well as some popular classics. The 12 and 12 Pro have different color choices, so if you have your heart set on a particular shade, you might not be able to get your preferred model in that color. iPhone 12 mini and iPhone 12 The iPhone 12 mini and iPhone...
studio buds family

Beats Studio Buds Debuting Today With Active Noise Cancellation, Stemless Design, and More for $150

Monday June 14, 2021 8:00 am PDT by
We've seen a lot of teasers about the Beats Studio Buds over the past month since they first showed up in Apple's beta software updates, and today they're finally official. The Beats Studio Buds are available to order today in red, white, and black ahead of a June 24 ship date, and they're priced at $149.99. The Studio Buds are the first Beats-branded earbuds to truly compete with AirPods...
youtube apple tv

YouTube Discontinuing 3rd-Generation Apple TV App, AirPlay Still Available

Wednesday February 3, 2021 3:09 pm PST by
YouTube is planning to stop supporting its YouTube app on the third-generation Apple TV models, where YouTube has long been available as a channel option. A 9to5Mac reader received a message about the upcoming app discontinuation, which is set to take place in March.Starting early March, the YouTube app will no longer be available on Apple TV (3rd generation). You can still watch YouTube on...
maroon5memories

Apple Collaborates With Maroon 5 to Add 'Memories' Song to Photos App

Wednesday September 25, 2019 12:02 pm PDT by
Apple has teamed up with Maroon 5 to add the group's new song "Memories" to the Memories feature in the Photos app, allowing it to be used for photo slide show creations, reports Billboard. "Memories" will be available as a soundtrack option for a limited time and it is available to iPhone and iPad users running the latest iOS 13 and iPadOS software. Memories in the Photos app are created ...
affinity designer contour tool

Serif Updates Affinity Photo, Designer, and Publisher With New Tools and Functions

Thursday February 4, 2021 1:58 am PST by
Serif today announced across-the-board updates for its popular suite of Affinity creative apps, including Affinity Photo, Affinity Designer, and the Apple award-winning Affinity Publisher for Mac, all of which were among the first professional creative suites to be optimized for Apple's new M1 chip. "After another year which saw record numbers of people switching to Affinity, it's exciting to...
original iphone

Phil Schiller Says iPhone Was 'Earth-Shattering' Ten Years Ago and Remains 'Unmatched' Today

Monday January 9, 2017 7:15 am PST by
To commemorate the tenth anniversary of the iPhone, Apple marketing chief Phil Schiller sat down with tech journalist Steven Levy for a wide-ranging interview about the smartphone's past, present, and future. The report first reflects upon the iPhone's lack of support for third-party apps in its first year. The argument inside Apple was split between whether the iPhone should be a closed...
Top Stories 75 Thumbnail

Top Stories: Last-Minute iPhone 13 Rumors, Apple Announces App Store Changes, and More

Saturday September 4, 2021 6:00 am PDT by
The finish line is in sight! Apple's annual iPhone event is likely just a week or so away and all eyes will be on the company as it unveils the next version of its most popular product line. With any luck, we'll also see the next-generation Apple Watch and perhaps even some new AirPods. Other news this week saw Apple making some more changes to its App Store policies in response to a...
Top Stories 74 Thumbnail

Top Stories: iPhone 13 Nears Launch, Larger Apple Watch?, MacBook Pro and Mac Mini Rumors

Saturday August 28, 2021 6:00 am PDT by
August is rapidly drawing to close, which means Apple's annual iPhone launch event is right around the corner. iPhone 13 and Apple Watch Series 7 rumors are continuing to circulate, and we're also hearing about Mac updates likely coming a bit later. Apple is also finishing up work on its upcoming software updates like iOS 15, with some late-addition features starting to go live in beta while ...
iPhone 13 Wi Fi 6E feature update

Wi-Fi 6E Explained: What It Could Mean for iPhone 13 and Beyond

Monday August 2, 2021 8:00 am PDT by
The iPhone 13 is widely expected to come with Wi-Fi 6E capabilities, and while it may seem rather nuanced to the average consumer, with only improved speeds and being "up to date" in the realm of Wi-Fi technology, it's actually a fairly significant improvement, laying the groundwork for much of what we know the future holds. To truly understand Wi-Fi 6E, MacRumors sat down for an exclusive...