Touch ID is a feature introduced by Apple to many of their iPhone, iPad and MacBook products. It allows the user to unlock their device with just the touch of thumb or finger, based on the principle that their fingerprint is individual to them so only they should be able to unlock it. This raises many questions as to how this feature works and data security, as using this type of identification data often raises controversy.
How does it work?
Apple’s Touch ID is an advanced technology that uses a capacitive touch or capacitive sensing, which is based on capacitive coupling, to capture each fingerprint. This technology has been present in some phones since 2007, but was popularised by Apple on its introduction to the iPhone 5s in 2013. A sensor is built into a stainless steel ring behind a laser-cut sapphire crystal lens. This sensor consists of many tiny, conductive plates which are narrower than the ridges of your fingerprints. A small current is passed through the finger and difference in distance created by the ridges and furrows of the fingerprint will mean a difference in the charge or capacitance. The sensor detects this and uses it to create a map of the skin by creating high-resolution images of small sections. Software can then analyse this and categorise the print pattern into loop, whorl or arch shapes. Apple claim the technology also maps out details within ridges.
Result- Can this read a real Fingerprint?
A fingerprint is defined as an impression of the pattern of ridges on the palmar surface of the end joint of each finger and thumb. Due to the fact this apple technology can detect ridge pattern and use this information to distinguish the user of the device it would seem this technology is able to read a real fingerprint. However, the data is encrypted and stored on the device mathematically, so no images of the actual print can be accessed using the stored data on the phone. When the finger is scanned again on touch, this is quickly converted to mathematical data and compared to the data stored in the phone as to whether there print matches. It should also be noted that fingerprint scanners used in devices are not as accurate as other, larger scale scanners.
A more traditional, larger scale method of fingerprint scanning is the use of optical scanners. These use visible light to capture an image of a latent fingerprint but are unlikely to be found in portable devices because of their bulk. Optical scanning is the key method used by EVISCAN technology to identify and visualise latent fingerprints. Click here to find out more.
Sources
Apple Inc. – About Touch ID advanced security technology. (2017) (https://support.apple.com/en-gb/HT204587)
Collins English Dictionary Online – Fingerprint. (2018) (https://www.collinsdictionary.com/dictionary/english/fingerprint)
Ben Gilbert, Engadget UK – iPhone 5s fingerprint sensor called Touch ID, recognizes your thumb on the Home button: here’s how it works and what it does. (2013) (https://www.engadget.com/2013/09/10/iphone-5s-fingerprint-sensor/?guccounter=1)
Andy Greenberg, Forbes Online – Apple’s New iPhone ‚Touch ID‘ Makes Fingerprint Scans Easy, But Don’t Ditch Passcodes Yet. (2013) (https://www.forbes.com/sites/andygreenberg/2013/09/10/apples-new-iphones-touch-id-makes-fingerprint-scans-easy-but-dont-ditch-your-passcode-yet/#6b400b918037)
Techquckie – How Does Fingerprint Scanning Work? (2018) (https://www.youtube.com/watch?v=oCY5sPkkaTM&t=92s)
Fernandez-Saavedra et al. – Small fingerprint scanners used in mobile devices: the impact on biometric performance. (2016) IET Biometrics, 5(1), pp.28-36.
