Generate new SSH key pair:

ssh-keygen -o -a 250 -t ed25519 -f ~/.ssh/id_ed25519 -C "[email protected]"

-o — Saves the private-key using the new OpenSSH format vs. the older PEM format (implied when key type is ed25519).

-a — Number of KDF (Key Derivation Function) rounds. Higher numbers are better; with modern hardware the passphrase verification tradeoff is negligible if not unimportant. 100 rounds should be considered an absolute minimum.

-t — Specifies the type of key. The Ed25519 was introduced on OpenSSH version 6.5 using the EdDSA implementation (Twisted Edwards curve) that offers a better security with faster performance compared to DSA or ECDSA.

-f — Specifies the filename and location of the generated key pair files.

-C — Specifies a comment which is useful for identifying the machine or user that the key pair is associated with, for example [email protected]@dell-xps9000.

Links

https://linux.die.net/man/1/ssh-keygen 

https://medium.com/risan/upgrade-your-ssh-key-to-ed25519-c6e8d60d3c54  — [Archived]