The Nitrokey 3C NFC is a hardware security key with open-source firmware and support for a range of authentication protocols, making it suitable for most users. It can even store your passwords and encrypt your emails, files, or hard disks. During previous tests, I had trouble using the key's wireless function, but this time around, connecting was a breeze. With that in mind, I have raised the Nitrokey's score by half a star since my last review. That said, it's expensive at $75.73, especially compared with the elegant and straightforward Yubico Security Key C NFC ($29), an Editors' Choice winner.

Pricing and Perks: Costlier Than the Competition, But It Supports More Authentication Standards

Nitrokey is a German company that produces open-source security software and privacy-focused hardware. I evaluated the Nitrokey 3C NFC, which costs €65 ($75.73 at the time of writing). The Nitrokey 3A is the USB-A version of the same security key I tested.

(Credit: Kim Key)

The Nitrokey 3C NFC's authentication standards are a bit more varied than those of less expensive and more popular starter keys, such as Google's Titan Key ($30). Both support WebAuthentication (WebAuthn), CTAP2/FIDO2, CTAP1/FIDO U2F 1.2, HMAC-Based One-Time Password (RFC 4226), and Time-Based One-Time Password (RFC 6238).

Like the pro-level $58 YubiKey 5C NFC, the Nitrokey 3C NFC enables you to encrypt data, such as emails and information stored on hard drives, and unlock it using GnuPG, an open-source encryption and decryption software.

Nitrokey 3-series keys also support email encryption via OpenPGP, S/MIME, Thunderbird, or Outlook. You can use Nitrokey to encrypt your hard disks using LUKS or VeraCrypt. The Nitrokey can also function as a smart card, and supports the following standards: OpenPGP Card (GnuPG), NIST PIV, PKCS#11 (OpenSC), S/MIME, Windows MiniDriver, and X.509.

Business users may be interested in Nitrokey's support for passwordless logins on computers managed by Azure Active Directory. The aforementioned YubiKey 5C NFC is compatible with a wide range of enterprise services, including AWS Identity and Access Management (IAM), Duo Security, ForgeRock, Idaptive, Microsoft Azure Active Directory, Okta, OneLogin, and Ping Identity.

Features: Functional Design and Solid Build, Upgradable Firmware

(Credit: Kim Key)

The Nitrokey 3C NFC isn't quite as sleek-looking as the YubiKeys, with all their cool curves and signature brass verification buttons. It is remarkably solid-feeling for such a little device, though. On one end is a USB-C connector, and on the other side is a non-reinforced hole for a key ring. A light flashes on the key when you touch it to confirm your identity, but it lacks a fingerprint reader.

(Credit: Nitrokey/PCMag)

Nitrokeys use upgradable and open-source firmware, unlike YubiKeys. This means that you can update the key when new features are announced, rather than having to buy a new one, which is preferable.

Firmware updates are available via Nitrokey's desktop apps. I downloaded Nitrokey App 2 on Windows to test the device. The app includes a section for storing passwords, but it lacks auto-filling and password generation tools you'd expect from a dedicated local password manager, such as Enpass or LogMeOnce.

(Credit: Nitrokey/PCMag)

It's very easy to find information about all of Nitrokey's products via the company's support pages. There you can find answers to frequently asked questions, step-by-step instructions for using keys, compatibility and feature lists, and a firmware update guide. It's a significant change that warrants a half-point increase in the review score.

Hands-On Testing: Reliable Wireless and USB-C Connectivity

(Credit: X)

The Nitrokey 3C NFC is compatible with Linux, macOS, and Windows. The website documentation states the device offers "some support for Android and iOS." I tested the Nitrokey using a desktop computer running Windows and an Android mobile device.

First, I logged into a test Proton Mail account and added the Nitrokey by visiting the Accounts and Password section. I attached the key to my account and was able to log in without any problems, which is ideal.

During a previous evaluation, I had trouble using the Nitrokey's NFC capabilities with my mobile devices. This time around, I didn't have any trouble logging into my test email accounts on an Android phone using the Nitrokey's NFC connectivity.

To finish the mobile compatibility section of the evaluation, I used the Nitrokey 3C NFC's USB-C port to connect to the Android device. I added the Nitrokey 3C NFC to a test account, logged out, then logged back in without any issues.