> For the complete documentation index, see [llms.txt](https://epochsec.gitbook.io/daily-activities-best-practices/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://epochsec.gitbook.io/daily-activities-best-practices/two-factor-authentication/basic-notes.md).

# Basic Notes

* The YubiKey 5C series is a compact USB authentication device that supports multiple protocols such as FIDO2/WebAuthn, FIDO U2F, OTP (One-Time Password), OpenPGP, and smart card (PIV).
* Yubikey devices are compatible with many ports, which are commonly found in modern laptops and smartphones.
* By requiring a physical key to access your accounts, the YubiKey 5C series adds an extra layer of security that is far more robust than traditional username and password combinations.