$ ssh-keygen -t ed25519 -a 100
Enter file in which to save the key (/puffy/.ssh/id_ed25519):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /puffy/.ssh/id_ed25519
Your public key has been saved in /puffy/.ssh/id_ed25519.pub
The key fingerprint is:
...