SSH/PGP

https://github.com/lfit/ssh-gpg-smartcard-config/blob/master/YubiKey_NEO.rst

https://www.esev.com/blog/post/2015-01-pgp-ssh-key-on-yubikey-neo/

https://developers.yubico.com/PGP/SSH_authentication/

Import PGP key

https://developers.yubico.com/PGP/Importing_keys.html

Additional info

https://www.yubico.com/2015/02/key-size-matter-cryptography/

https://www.yubico.com/2015/02/comparing-asymmetric-encryption-algorithms/

https://www.yubico.com/2015/02/big-debate-2048-4096-yubicos-stand/

Alternative

https://trezor.io/