I cannot understand that RECEIPIENT

[NerdHusky]

I wanted to try a public key first:

age -o id_ed25519.pub.age -r "ssh-ed25519 pub"  id_ed25519.pub
age: error: malformed SSH recipient: "ssh-ed25519 pub": ssh: no key found
age: report unexpected or unhelpful errors at https://filippo.io/age/report

Maybe I did wrong.
Now let's try the "real deal". Sure this can´t go wrong....

age -o id_ed25519.age -r "ssh-ed25519"  id_ed25519
age: error: malformed SSH recipient: "ssh-ed25519": ssh: no key found
age: report unexpected or unhelpful errors at https://filippo.io/age/report

And so I came here, hopeless.

[str4d]

The -r option takes the actual text of the recipient pubkey, because for a native age recipient that is a string age1..... It is not a type selector option like ssh-keygen -t ed25519. So if you want to use it this way, you'd need to take the entire content line from your id_ed25519.pub file and pass it as a string option for -r.

Instead, what you should do is use the -R option, which takes a path to a file containing a list of recipients. That is exactly what id_ed25519.pub is, so your command should be:

age -o file-to-encrypt.age -R  id_ed25519.pub file-to-encrypt

[NerdHusky]

Thank you very much man for taking the time for answering me!! This is SO helpful, thank you!!