PhotoDNA is a very simple algorithm. Reproducing what OP did to "reverse engineer" is not hard. If you really have the guts to try this go ahead and you'll be surprised. I'm living in the US with a greencard so I'm not touching the problem even with a laser pointer.
The techno-legal framework is worse than just "reversing the hashes is possible". You could brute force creation of matching images using a cloud service or online chat as an "oracle".
The techno-legal framework is worse than just "reversing the hashes is possible". You could brute force creation of matching images using a cloud service or online chat as an "oracle".