The Yubico YubiKey 5C Nano is a compact hardware authentication device for secure access to computers, networks, and online services. With a diameter of just 12.5 mm and a thickness of 3.3 mm, this USB-C device sits nearly flush in compatible ports, making it ideal for laptops and mobile devices where portability and minimal protrusion are priorities. The device supports multiple authentication protocols including FIDO2, FIDO U2F, PIV, OTP, and OpenPGP, providing versatile security solutions for both personal and business use. Its robust housing construction from composite materials is resistant to physical damage and environmental influences. The YubiKey 5C Nano operates without batteries or network connections, ensuring reliable performance even in offline scenarios. It features cryptographic capabilities with 2048-bit RSA and ECC P-256, as well as integrated tamper protection to guard against unauthorized access attempts. The device is compatible with Windows, macOS, Linux, Chrome OS, and mobile platforms via USB-C connections, and supports seamless integration with popular services such as Google, Microsoft, GitHub, and password managers. Weighing approximately 3 g, this authentication key provides enterprise-level security in an ultra-compact form, suitable for professionals who require strong two-factor authentication without compromising device portability. The YubiKey 5C Nano protects against phishing attacks and account takeovers while offering easy operation through touch-based authentication functionality.