The YubiKey 5 Nano FIPS is the certified sibling of the standard 5 Nano. The hardware and the protocols are identical; the difference is the paperwork. This key is FIPS 140-3 validated, the current US federal standard that replaces the 140-2 generation now being retired. If a contract, a government tender or an internal control says your authenticators must be FIPS validated, this is the version that satisfies the auditor. If nothing you sign asks for it, the standard YubiKey 5 will serve you just as well.
Physically it is a nano: a stub of USB-A that sits almost flush with the port and stays there. It is built for a fixed desktop or workstation that one person uses and does not want to unplug daily. There is no battery and no moving parts, and the key is crush- and water-resistant, so leaving it in the machine year-round is the intended use rather than a risk.
Running firmware 5.7, it carries the full YubiKey 5 protocol set: FIDO2 and WebAuthn for passkeys, FIDO U2F, PIV smart card, OATH-TOTP and OATH-HOTP, OpenPGP, YubiKey OTP, static password and HMAC-SHA1 challenge-response. That covers phishing-resistant sign-in to Microsoft 365 and Entra ID, smart-card login, and one-time codes for services that still rely on them, from a single key.
Our take: buy it when a compliance requirement genuinely names FIPS, and when the key will live in a desk-bound machine. It has no NFC, so it will not tap a phone, and it is USB-A, so it suits desktops rather than newer USB-C laptops. A nano is easy to forget and awkward to move between machines; if your people hot-desk or work from laptops, choose a larger or USB-C key instead.
