Use the ssh-keygen command to generate the key pairs.
ssh-keygen -b bits -a rounds -C comment -v
ssh-keygen -t ed25519 -a rounds -C comment -v
Note: If invoked without any arguments, ssh-keygen will generate an RSA key for use in SSH protocol 2 connections. (equivalent of -t rsa.)
For example:
ssh-keygen -b 7680 -a 100 -C 'Linux Mint Petra 64-bit guest' -v
or for the EdDSA scheme:
ssh-keygen -t ed25519 -a 100 -C 'Linux Mint Petra 64-bit guest' -v
By default, the keys are stored in ~/.ssh as id_rsa and id_rsa.pub.
To show the fingerprint of specific public key file:
ssh-keygen -l -v
