SSH using public key authentication to IOS
Create a user:
username test priv 15 secret supers3cr3tn0bdyw1llgue55
You need to make sure this public key is trusted by our router.
ip ssh pubkey-chain
copy the entire public key as appears in the cat id_rsa.pub including the ssh-rsa and username@hostname.
please note that some IOS versions will accept maximum 254 characters.
you can paste multiple lines.
Please also make sure that you generate RSA keys on Server larger than 768 bits.
You can also set SSHv2 on server side (although strictly speaking it's not required if you're using SSH 1.99)
ip ssh version 2