The YubiKey 5C Nano FIPS is a hardware security key designed for multi-factor authentication in government and regulated organizations. The device connects via USB-C and features a nano form-factor intended to remain inserted in the device. The product is FIPS 140-2 validated (Overall Level 2, Physical Security Level 3) and supports multiple authentication protocols including FIDO2/WebAuthn, FIDO U2F, Yubico OTP, OATH-TOTP, OATH-HOTP, Smart card (PIV), and OpenPGP. It provides 25 passkey slots, 32 OATH slots, and 24 PIV certificates. The device supports RSA cryptography (1024-4096 bits for OpenPGP, 1024-2048 for PIV) and ECC (P-256, P-384), along with modern curves including Ed25519, X25519, secp256k1, and brainpool variants. It operates as an HID keyboard, CCID smart card, and FIDO HID device. The hardware is IP68 rated for water and dust resistance, with crush resistance up to 25 N·m. It requires no batteries or network connectivity and is rated for 100,000+ USB insertion cycles and 500,000+ write/erase cycles. The device is manufactured in Sweden and programmed in the USA. Compatible with Windows, macOS, Chrome OS, Linux, Chrome, and Edge browsers. Works with Google and Microsoft accounts, identity access managers, and password managers.