Pattern Lock is a popular protection method for Android devices, but it could be putting you at risk
Lock patterns are a popular way to secure Android smartphones, as they are a lot easier to remember than PIN codes or text passwords.
In fact, around 40% of Android owners opt for this lock method, which requires them to draw a secret pattern on a grid of dots to gain access to the device.
However, security experts have warned that the lock pattern system can be cracked within just five attempts – and more complicated patterns are the easiest to crack.
According to the researchers from Lancaster University, Northwest University in China, and the University of Bath, all it takes to break into the device is a camera phone and some simple computer vision software.
By covertly filming the owner when they are drawing their Pattern Lock shape to unlock their device, the software is able to track their fingertip movements relative to the screen.
Within seconds the algorithm produces a small number of possible patterns to access the Android phone or tablet.
The attack works even when the video footage is unable to capture what is on the screen, and regardless of the size of the device.
Results are accurate on video recorded on a mobile phone from up to two and a half metres away – or up to nine metres away with footage recorded on a digital SLR camera, according to the resarchers.
This means an attack of this kind could easily be carried out in a busy cafe or restaurant, for example, allowing thieves to unlock phones after stealing, or quickly install malware on devices while their owners were distracted.
Researchers tested the attack on 120 unique patterns from 215 users, and found that they were able to crack more than 95% of patterns within five attempts.
Ironically, they also found that complex patterns were easier to crack than simple ones, because they help the fingertip algorithm to narrow down the possible options.
“As well as for locking their devices, people tend to use complex patterns for important financial transactions such as online banking and shopping because they believe it is a secure system,” said Dr Zheng Wang, principle investigator and co-author of the paper.
“However, our findings suggest that using Pattern Lock to protect sensitive information could actually be very risky.”
How to protect yourself
If you’re worried about your lock pattern being cracked, there are steps you can take to protect yourself, such as covering your fingers when drawing the pattern.
The researchers suggest that pattern lock designers should also mix pattern locking with other activities, such as entering a sentence using Swype-like methods.
Adjusting the screen colour and brightness while the pattern is being drawn could also confuse the recording camera.
Of course, there’s always the option of switching to a different authentication method – such as a fingerprint reader or iris scanner, if your smartphone has one.