On: Thermal images reveal what parts of a screen were ...

[alex-]

Another (cheaper?) solution would be to randomise the location of the keys each unlock attempt.

It would cause me a massive problem - I basically only remember my pattern

[prawn → alex-]

One of my banks does this for online PIN entry and it's amazing how much it slows you down not being able to do it via muscle memory.

[ComodoHacker → alex-]

It would also make it impossible to unlock device off-sight (in the pocket) and increase chances of shoulder-surfing.

The proper solution would be let user draw some figure anywhere on the screen then OCR it.

[test1235 → alex-]

I use a pattern for my unlock, and you don't even need thermal imaging - you can see the smear left on the screen by my finger.

[Qantourisc → alex-]

Android -> Settings -> Lock screen -> Scramble pin layout.

If you are talking in general, hmmm yea hard, especially if it's mandatory.

[macspoofing → alex-]

Or move the location of the keys around the screen (but keep the order)