create ssh keys
ssh-keygen -t rsa -C "[email protected]"
$ ssh-keygen -t rsa -b 4096 -C "[email protected]"
cat ~/.ssh/id_rsa.pub | ssh [email protected] "mkdir -p ~/.ssh && chmod 700 ~/.ssh && cat >> ~/.ssh/authorized_keys"
$ ssh-keygen -t ed25519 -C "[email protected]"