There is a support page : https://proton.me/support/pay-with-bitcoin

Oh right, my bad x) I agree, it’s a little bit akward to use su then cat everytime.

That could be possible but for the moment I didn’t encouter any problem with cat. I think I’m going to stick with it for the time being.

Yep that’s right, but I use fdisk to check my drives before writing on them and it also requires sudo…

My favorite way to create a boot media is simply to use cat. No arguments, no shenanigans just a cat into the device :

cat debian.iso > /dev/sda

It’s actually a really good question. What you’re explaining is called a collision, by creating the same hash with different numbers you can succesfully login.

This why some standard hashing function become deprecated and are replaced when someone finds a collision. MD5, which was used a lot to hash passwords or files, is considered insecure because of all the collisions people could find.