Apple's new Face ID feature, which will let people unlock the forthcoming iPhone X by simply looking at it, has left some feeling deeply unsettled.
The new technology uses a series of sensors and cameras on the front of the phone to map and learn its owners face over time. The company has lauded the new technology is the 'future of how we unlock iPhones and protect sensitive information'.
During Apple's keynote event at the Steve Jobs Theater in Cupertino, California, yesterday, Phil Schiller, the company's Senior Vice President of Worldwide Marketing, attempted to preempt fears about Face ID by saying it only works when a user's eyes are open.
He also said the facial data the iPhone X collects is only stored on the device and not a server.
Yet people were quick to express discomfort about the idea of giving Apple the digital blueprint of their face, the Telegraph reported.
The feature has big security questions hanging over it that will not be properly answered until its public release when the iPhone X starts shipping in November. Meanwhile Face ID has reopened the question of how much personal and sensitive data are we are comfortable with our phones knowing about us.
Facial recognition is clearly a step too far for some, yet consumers may not be aware of the full extent of what our phones already record about us.
Everywhere you go
Location tracking on smartphones is not a new phenomenon. However iPhones automatically collect data on everywhere its users go and how long they spend there.
Apple's Frequent Locations function is an automatic feature that the company says helps iPhones learn which places are significant to its users. The data is then used to improve functions such as route-planning.
You can see the location data your iPhone has collected on you, and turn it off if you wish, via your iPhone settings. First go to the Privacy tab, then go to Location Services and scroll down to System Services.
Once in there go to Frequent Locations and look in history. There will be a list the places your phone has recorded as significant.
Every photo you've ever taken - or deleted
Deleting a photo from your phone doesn't mean it's gone as smartphones still keep a record of the images created on them. This includes images sent to your phone - even if you haven't opened them.
Daniel Martin, Head of Criminal Defence at law firm Blaser Mills LLP, said police investigators routinely retrieved images people thought they had deleted from their phones.
He said: "Image data is immediately 'cached' when it is received by a phone and can be recovered from what are known as 'unallocated clusters' in the phone's memory, even after the image itself has been deleted.
"The larger a phone's memory the more unallocated space is available for cached data to be stored, which is then only deleted as the available memory is used up."
Voice assistants such as the iPhone's Siri and the Google Assistant are now a ubiquitous feature on smartphones. In 2015 it emerged that Google stores all the voice recordings it receives when people talk to its voice-control features.
Android users can even go and listen back to all the queries and commands they have issued to the Google Assistant by visiting Google's voice and audio activity page.
Google's voice activity can be turned off, but this won't stop your phone recording your voice. It means the recordings will be logged as anonymous and not directly linked to your account.
Since Apple first introduced Touch ID in 2013, fingerprint reading has become an integral part of modern smartphones. Thus far consumers have been happy to hand over this sensitive piece biometric data as a trade-off for enhanced security on their devices. Yet manufacturers have varying methods of storing users' fingerprints.
Apple's says iPhones don't store an actual image of a fingerprint but instead rely only on a mathematical representation. As with Face ID, Apple says the data is stored only on the phone in a Secure Enclave in its chip. Meaning the company doesn't have a global database of people's fingerprints.
Meanwhile other manufactures have come under scrutiny for the measures they take to protect users' fingerprint data. In 2015 HTC came under fire for storing fingerprints images an unencrypted "world readable" image files, which were potentially vulnerable to hackers.