-a: Is the KDF (Key Derivation Function) rounds. Higher result in slower passphrase verification, increasing the resistance to brute-force cracking.
-t: Specifies the type of key, in this case Ed25519.
-f: The filename of the generated key file.
ssh-keygen -o -a 100 -t ed25519 -f ~/.ssh/id_ed25519 -C "name"