ssh-keygen(1) -t ed25519 -o -a 100
authentication key generation, management and conversion
-t type
        Specifies the type of key to create.  The possible values are “rsa1” for protocol version 1 and
        “dsa”, “ecdsa” or “rsa” for protocol version 2.
-a trials
        Specifies the number of primality tests to perform when screening DH-GEX candidates using the -T
source manpages: ssh-keygen