YubiKey (hardware security key)

A YubiKey is a hardware security key (USB/NFC) designed by Yubico that stores non-extractable cryptographic secrets and supports FIDO2/WebAuthn, OpenPGP, and PIV protocols. As part of a qualified signature (QES), a YubiKey (or an equivalent device compliant with Annex II of eIDAS) can serve as a Qualified Signature Creation Device (QSCD): the private key associated with the qualified certificate never leaves the hardware, guaranteeing the highest level of assurance over the signer''s identity. On a Certyneo admin account, a YubiKey can also protect admin access via hardware MFA.