[deaddodo]

Just to add to this: intentional/digital blur is even easier to undo as the source image is still mostly there. You just have to find the inverse metric.

This is how one of the more notorious pedophiles[1] was caught[2].

1 - https://en.wikipedia.org/wiki/Christopher_Paul_Neil

2 - https://www.bbc.com/news/world-us-canada-39411025