A remarkable new method that could be used by thieves to easily steal your smartphone PIN has been discovered.
After you enter your PIN or passcode, thieves could use a thermal imaging camera to record the heat marks left on the screen, researchers warned.
The heat traces transferred from your fingertips to the screen would be enough to give away access to your smartphone, researchers at Stuttgart University have discovered.
The heat traces can be recovered as much as 30 seconds after you’ve touched the screen and are then used to reconstruct the password.
If you enter a four digit PIN you would unknowingly leave behind four heat traces on the screen.
The researchers say that a thermal imaging camera set up to record temperatures between 66 and 90 degrees Fahrenheit would be able to pick up the traces left of the screen.
Special software can then be used to change the colour of the image in order to reveal the heat traces.
This then makes is easy for your PIN to be deciphered, with the relative heat of each tap on the screen likely to determine the order you pressed the digits.
The same technique can be used to work out Android’s PIN pattern, tracing the path of your finger as it moves across the screen.
Researchers said the technique is even more effective when used on an Android PIN pattern.
As long the the thermal image is taken within 15 seconds of you entering the pattern, there is an almost 90 per cent success rate.
If your Android pattern does not overlap in any way, then the success rate is even greater at a staggering 100 per cent.
In a video uploaded to YouTube, the researchers demonstrated how they used thermal imaging to steal a smartphone.
Researchers said that one way to avoid falling victim to this kind of attack is to cover your smartphone screen with your hand when entering your PIN. This results in multiple heat traces forming across the screen making it difficult to identify any patterns.
They also said that increasing the brightness on your display raised the temperature of your screen which reduces the time your heat pattern is visible.
HT: The Atlantic