Apple is working on a feature that will let you unlock your iPhone using your face instead of a fingerprint.

For its redesigned "10th anniversary" iPhone, set to go on sale later this year, Apple is testing an improved security system that allows users to log in, authenticate payments, and launch secure apps by scanning their face, according to people familiar with the product. This is powered by a new 3D sensor, added the people, who asked not to be identified discussing technology that's still in development. The company is also reportedly testing eye scanning to augment the system.

The sensor's speed and accuracy are focal points of the feature. It can scan a user's face and unlock the iPhone within a few hundred milliseconds. It is designed to work even if the device is laying flat on a table, rather than just close up to the face. The feature is still being tested and may not appear with the new device. However, the intent is for it to replace the Touch ID fingerprint scanner. An Apple spokesman declined to comment.

In testing, the face unlock feature takes in more data points than a fingerprint scan, making it more secure than the Touch ID system. Apple introduced Touch ID in 2013 with the iPhone 5s for unlocking the phone and it added support for authenticating payments and logging into apps a year later.

Apple is not the first to use different forms of biometric authentication. In its latest phones, Samsung included iris scanners that let users unlock their phones and make payments by scanning their eyes. Samsung's feature on its Galaxy S8 smartphone launched to poor reviews as users were able to trick the sensor with printed photo copies of a person's eyes. Apple's sensor has 3D depth perception, which means the system is less likely to be duped by 2D pictures.

The new iPhone's debut will mark the biggest upgrade in years to the company's most important product. Apple launched the iPhone 7 and iPhone 7 Plus last year, focusing on camera and speed upgrades while using the same design as the previous iPhone 6s (which essentially added a pressure-sensitive screen to the 2014 iPhone 6's design). The iPhone generates nearly two-thirds of Apple's sales, and has become a central hub for products like the Apple Watch, Apple TV, and the new HomePod.

For the device's decade anniversary, Apple is also testing a new glass casing, steel edges, and a larger display that fits into a smaller overall body, according to previous reports. The new phone will have glass on both the front and back that curves at the edges. Between the glass front and back is a stainless steel frame that houses power and volume controls.

The front and back glass looks continuous because of how thin the steel surrounding frame is, people familiar with the device said. The edge-to-edge display's only break will be a cutout in the glass to fit in the earpiece, front facing camera, and facial recognition sensor.

The redesigned iPhone will use an OLED screen, which reproduces colours more crisply, while the company is also planning updates to the iPhone 7 and iPhone 7 Plus that still include standard LCD screens. The new 3D sensor is being tested for the OLED version. All three phones will include faster, more efficient processors based on a 10-nanometre production process.

The nearly all-screen front on the revamped iPhone means it will be about as big physically as the iPhone 7, but will have a display roughly the size of the one on the larger iPhone 7 Plus. The new device will have slimmer side bezels around the screen and eliminate the physical home button in favour of a virtual software-based button. Apple has faced challenges integrating the Touch ID fingerprint scanner into this new screen, people familiar with Apple's work have said, but the 3D sensor may solve that issue.

Bloomberg