On Tuesday, 6 August 2019 19:52:32 UTC+1, Adrian Caspersz wrote:
I'd go DIY, some sort of two-factor authentication.
i.e.
1. machine learning, so that what looks like a cat is identified as
being a cat,

It's been mentioned here before, but someone did one with pattern recognition so that "cat" is admitted, but "cat+mouse" is not admitted.

Owain