Loic Dachary 🏊 is a user on pouet.dachary.org. You can follow them or interact with them if you have an account anywhere in the fediverse. If you don't, you can sign up here.
The i9300 recovery images for twrp do not match the signature or md5. It is probably just an error but scary anyway.
https://github.com/TeamWin/Team-Win-Recovery-Project/issues/1109
My bad, they match. The problem comes from the fact that clicking the link https://dl.twrp.me/i9300/twrp-3.2.0-0-i9300.img does not work in the same way in a browser or with wget. I was trying to get the md5sum of an HTML page... Tricky :-)