https://peterlyons.com/problog/2017/12/openssh-ed25519-private-key-file-format/
https://github.com/openssh/openssh-portable/blob/master/PROTOCOL.key
	canonical: https://cvsweb.openbsd.org/src/usr.bin/ssh/PROTOCOL.key?annotate=HEAD
https://stackoverflow.com/a/56300901/733214
https://stackoverflow.com/a/59283692/733214
https://coolaj86.com/articles/the-openssh-private-key-format/
https://coolaj86.com/articles/the-ssh-public-key-format/