• https://medium.com/risan/upgrade-your-ssh-key-to-ed25519-c6e8d60d3c54
• https://www.mittwald.de/blog/mittwald/howtos/ssh-key-erstellen
• https://www.ssh.com/ssh/keygen/
• https://linux.die.net/man/1/ssh-keygen

How to create a SSH key.

TMPDATE="$( printf '%(%Y%m%d-%H%M%S)T\n' -1 )"; ssh-keygen -a 100 -t ed25519 -f "${HOME}/.ssh/id_ed25519-${USER}-${HOSTNAME:-$(hostname)}-${TMPDATE}" -C "$USER@${HOSTNAME:-$(hostname)}-${TMPDATE}";

ssh-keygen -t rsa -b 4096 -f ~/.ssh/id_rsa -C "$USER@${HOSTNAME:-$(hostname)}"

~~DISCUSSION~~