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. In the context 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 on the signatory's identity. On a Certyneo administration account, a YubiKey can also be used to protect admin access via hardware MFA.