If the problem is with perverts looking at child porn then solve it by stopping the small number of perverts from being able to look at it rather than installing software or hardware in every internet capable device with a graphical display (which will then lead to homebrew devices being illegal etc).
A fairly simple lo-tech way would be to stop perverts looking at porn by removing the sight of convicted paedophiles. This prevents the convicted ones reoffending and provides a significant dis-incentive for the others. You could either do this permanently ala the middle ages (with a hot poker in the eye), or with some high tech medical procedure (detach the optical nerve under general anaesthetic, possibly reversable after a sentance has been served), or ironically, by strapping black boxes over their heads.