Touch ID

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Touch ID is a fingerprint recognition feature, designed and released by Apple Inc., and is currently available on the iPhone 5s, iPhone 6, iPhone 6 Plus, iPhone 6s, iPhone 6s Plus, iPhone SE, iPad Air 2, iPad mini 3, iPad mini 4, iPad Pro, iPad Pro 9.7, iPhone 7 and iPhone 7 Plus.

On September 19, 2015, Apple introduced the second generation Touch ID, which is twice as fast as the first generation sensor.

Apple says Touch ID is heavily integrated into iOS devices, allowing users to unlock their device, as well as make purchases in the various Apple digital media stores (iTunes Store, the App Store, iBookstore), and to authenticate Apple Pay online or in apps. On announcing the feature, Apple made it clear that the fingerprint information is stored locally in a secure enclave on the Apple A7 and later chips, rather than stored remotely on Apple servers or in iCloud, making it very difficult for external access.


The first mobile phone with a fingerprint scanner was the Motorola Mobility Atrix 4G in 2011.[1] The iPhone 5s unveiled on September 10, 2013 was the first phone on a major US carrier since then to feature the technology.[2] Following Apple's introduction in 2013, most other smartphone makers included fingerprint scanning in their high-end phones during 2014 and 2015,[3] starting with the Samsung Galaxy Alpha 4G. With Android 6.0 (Android Marshmallow, released October 2015) they can now also be integrated into the operating system like Touch ID is in iOS.

In 2012, Apple acquired AuthenTec, a company focused on fingerprint reading and identification management software, for $356 million.[4] The acquisition led commentators to expect a fingerprint reading feature.[4][5]

A leak on September 3, 2013, suggested that the feature would be coming to the iPhone,[6] while an alleged user guide showing the feature leaked just hours before the announcement came.[7] Wells Fargo analyst Maynard Um predicted on September 4, 2013, that a fingerprint sensor in the iPhone 5s would help mobile commerce and boost adoption in the corporate environment.[8] "As consumers increasingly rely on mobile devices to transact and store personal data, a reliable device-side authentication solution may become a necessity," Um said.[8] Apple's Vice President of Marketing, Phil Schiller, announced the feature at Apple's iPhone media event on September 10, 2013,[5] spending several minutes (the last major portion of the conference) discussing the feature.

With the unveiling of the iPhone 6 and 6 Plus at a keynote event on September 9, 2014, Touch ID was expanded from being used to unlock an iPhone and authenticating iTunes and App Store purchases to enable for purchases by Apple Pay. The iPhone 6s incorporates an markedly faster second-generation Touch ID fingerprint sensor that is up to twice as fast as the older, first-generation sensor found in the 5s, 6, and SE phones. As of September 2016, the iPhone 6S, 6S Plus, 7, and 7 Plus are the only Apple devices which use the second generation sensor. The new Touch ID unlocks almost instantly and posed an issue as it unlocks too fast to read notifications on the lock screen. This will be remedied with the forthcoming iOS 10 update in which a user must press the home button to have the home screen appear. Solely placing a finger on the sensor will only unlock the iPhone.

USAA has released their figures and as of the end of 2015 over one-million members are using Apple's Touch ID, utilizing their fingerprint to securely log on to the USAA Mobile Application on Apple's iPhones and iPads.[19]


Generation Model


Components of Touch ID.

Touch ID is built into the home button, which is built of laser-cut[9] sapphire crystal, which does not scratch (scratching would prevent Touch ID from working).[10] It features a stainless steel detection ring to detect the user's finger without pressing it. The feature does not work without contact with this ring. There is no longer a 'squircle' icon in the home button, nor is it concave.

The sensor uses capacitive touch to detect the user's fingerprint.[10] The sensor has a thickness of 170 µm, with 500 pixels per inch resolution. The user's finger can be oriented in any direction and it will still be read.[4] Apple says it can read sub-epidermal skin layers,[11] and it will be easy to set up and will improve with every use.[9] The sensor passes a small current through one's finger to create a "fingerprint map" of the user's dermis. Up to 5 fingerprint maps can be stored in the Secure Enclave.

Security and privacy[edit]

Touch ID can be bypassed using passcodes,[12] thus on account of it presenting a new different way for access to the device, it represents a net security decrease for an individual device. Apple claims that average user security is increased however because users who formerly had no passcode at all will now use Touch ID. Fingerprint data is claimed to be stored on the secure enclave of the Apple A7, A8, A8X, A9, A9X or A10 Fusion chip of the device itself, and not on Apple servers, nor on iCloud. From the Efficient Texture Comparison patent[13] covering Apple's TouchID: "In order to overcome potential security drawbacks, Apple's invention includes a process of collapsing the full 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. Numerous other exemplary embodiments are also possible, and any other exemplary pattern calculation can be used, where the exemplary pattern includes enough associated information to narrow the candidate list, while omitting enough associated information that the unsecured pattern cannot or cannot easily be reverse engineered into a matching texture."

[5][11] If the user's phone has been rebooted, or has not been unlocked for 48 hours, only the user's passcode, not a fingerprint, can be used to unlock the device.[12]

In September 2013, the German Chaos Computer Club announced that it had bypassed Apple's Touch ID security. A spokesman for the group stated: "We hope that this finally puts to rest the illusions people have about fingerprint biometrics. It is plain stupid to use something that you can't change and that you leave everywhere every day as a security token."[14][15] Similar results have been achieved by using PVA Glue to take a cast of the finger.[16]


In a 2013 opinion piece, Kevin Roose published in New York Magazine the assumption that consumers are generally not interested in fingerprint recognition, preferring to use passcodes instead. Traditionally, he wrote, only businesspeople such as Bloomberg employees used biometric recognition, although they believe Touch ID may help bring fingerprint recognition to the masses. Roose stated the feature will also allow application developers to experiment, should Apple open up access to Touch ID later on (which they have done).[17]

Roose also noted that complementary metal oxide semiconductor (CMOS) sensors, such as those found on Touch ID, generally wear out and become unusable after some period of time, and while Apple may have found a way to manufacture the sensors better, if the sensors stop working, users may just switch back to using their passcode, making fingerprint recognition a non-starter once again. Roose also noted that fingerprint technology still has some issues, such as the potential to be hacked, or of the device's not recognizing the fingerprint (for example, when the finger has been injured).[17]

Adrian Kingsley-Hughes, writing for ZDNet, said Touch ID could be useful in bring your own device situations. He said the biometric protection adds another layer of security, removing the ability of people to look over others' shoulders and read their passcode/password. He added that Touch ID would prevent children from racking up thousands of dollars in unwanted purchases when using iPhones owned by adults. He observed that Touch ID was Apple's response to the large number of iPhone crimes, and that the new feature would deter would-be iPhone thieves.

Moreover, he notes that the feature is one of the few that distinguish the iPhone 5s from the 5C.[18] Roose also stated the feature is intended to deter theft.[17] However, Brent Kennedy, a vulnerability analyst at the United States Computer Emergency Readiness Team, expressed concern that Touch ID could be hacked and suggested that people not rely on it right away.[19] Forbes noted a history of fingerprints being spoofed in the past, and cautioned that the fingerprints on a stolen iPhone might be used to gain unauthorized access. However, the article did say that biometrics technology had improved since tests on spoofing fingerprint readers had been conducted.[19]

Galaxkey was the first company to deploy encrypted email using Touch ID and thus implement two-factor authentication on an iOS device. They noted that fingerprints could be used to gain authorized access to email and files on Touch ID-enabled devices.[19]

Kingsley-Hughes suggested the Touch ID as a form of two-factor authentication, combining something one knows (the password) with "something you are" (the fingerprint).[18] Forbes said that, if two-factor authentication is available, it will be an overall improvement for security.[19]

Forbes columnist Andy Greenberg said the fact that fingerprint data was stored on the local device and not in a centralized database was a win for security.[20]

New York Magazine noted that those wary of surveillance agencies such as the US National Security Agency may still choose not to use Touch ID.[17]


  1. ^ "List of All Fingerpring Scanner Enabled Smartphones". Web cusp. 
  2. ^ Newton, Casey (September 10, 2013). "Apple's new iPhone will read your fingerprint". The Verge. Retrieved September 11, 2013. 
  3. ^ "List of All Fingerprint Scanner Enabled Smartphones". Retrieved May 10, 2016. 
  4. ^ a b c Rosenblatt, Seth (September 10, 2013). "iPhone 5S comes with Touch ID fingerprint scanner". CNET. Retrieved September 11, 2013. 
  5. ^ a b c Valazco, Chris (September 11, 2013). "Apple's Touch ID Is A 500ppi Fingerprint Sensor Built Into The iPhone 5S Home Button". TechCrunch. Retrieved September 11, 2013. 
  6. ^ "iPhone 5S : Une photo du bouton Home avec lecteur d'empreintes digitales ?!". NowhereElse. September 3, 2013. Retrieved September 11, 2013. 
  7. ^ "iPhone 5S : Le lecteur d'empreintes digitales confirmé ?!". NowhereElse. September 10, 2013. Retrieved September 11, 2013. 
  8. ^ a b Hughes, Neil (September 4, 2013). "Fingerprint sensor in Apple's 'iPhone 5S' predicted to boost mobile commerce, enterprise adoption". AppleInsider. Retrieved September 11, 2013. 
  9. ^ a b "Apple Announces iPhone 5S - The Most Forward-Thinking Smartphone in the World". The Wall Street Journal. September 10, 2013. Retrieved September 11, 2013. [dead link]
  10. ^ a b "Apple announces iPhone 5S: Touch ID fingerprint security, 64-bit A7 CPU, new gold option coming Sept. 20". AppleInsider. September 10, 2013. Retrieved September 11, 2013. 
  11. ^ a b Gilbert, Ben (September 10, 2013). "iPhone 5s fingerprint sensor called Touch ID, recognizes your thumb on the Home button: here's how it works and what it does". Engadget. Retrieved September 11, 2013. 
  12. ^ a b "Apple: New iPhone Not Storing Fingerprints, Doesn't Like Sweat". Digital. The Wall Street Journal. September 11, 2013. Retrieved September 11, 2013. 
  13. ^ "Efficient Texture Comparison". Digital. US Patent & Trademark Office. May 18, 2012. Retrieved November 21, 2013. 
  14. ^ Rieger, Frank (September 21, 2013). "Chaos Computer Club breaks Apple Touch ID". Chaos Computer Club. Retrieved September 21, 2013. 
  15. ^ Musil, Stephen (September 22, 2013). "Hackers claim to have defeated Apple's Touch ID print sensor". CNet. CBS Interactive Inc. Retrieved September 23, 2013. 
  16. ^ Rogers, Marc (September 23, 2013). "Why I Hacked Apple's TouchID, And Still Think It Is Awesome". Lookout. Retrieved September 23, 2013. 
  17. ^ a b c d Roose, Kevin (September 10, 2013). "Will the New iPhone's 'Touch ID' Feature Finally Make Fingerprint Scanning Happen?". New York (magazine). Retrieved September 11, 2013. 
  18. ^ a b Kingsley-Hughes, Adrian (September 10, 2013). "iPhone 5S with Touch ID is a big win for BYOD security". ZDNet. Retrieved September 11, 2013. 
  19. ^ a b c d Greenberg, Andy (September 10, 2013). "Apple's New iPhone 'Touch ID' Makes Fingerprint Scans Easy, But Don't Ditch Passcodes Yet". Forbes. Retrieved September 11, 2013. 
  20. ^ Steinberg, Joseph (September 13, 2013). "Your New iPhone Can Put Your Identity At Risk". Forbes. Retrieved July 5, 2014. 

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