Can You Use a USB as a FIDO2 Security Key? Here's What Nobody Explains to You
No, a regular USB drive cannot function as a FIDO2 security key or as a passkey. It can be used to lock access to your computer with tools like USB Raptor, but that's something completely different. In this post we explain the real difference and what options exist from €25.
What a normal USB does (and what it cannot do)
A USB drive stores files. With the right software, you can configure it so that Windows locks when you remove it — useful if you share a computer in an office or at home.
But that is not FIDO2 authentication. It doesn't work with Google, GitHub, Dropbox or any online service. It doesn't protect your accounts if someone has your password. It is not a security key.
The confusion comes from articles that mix two different things under the same title: "using a USB as a security key". Technically it's not incorrect, but the level of protection is not comparable.
What a real FIDO2 key needs
A certified FIDO2 key has a dedicated cryptographic chip inside. That chip generates a private key that never leaves the device — not when you connect it, nor when you lose it.
When a service like Google asks you to authenticate, the key signs a cryptographic challenge and returns the response. The service verifies that the signature is valid. At no point does a password travel across the network.
A generic USB drive doesn't have that chip. It cannot generate or store cryptographic keys of this type. There is no software that can make up for this hardware limitation.
There are open source projects that turn a Raspberry Pi Pico into a functional FIDO2 key. They are valid for learning and experimenting, but they do not have official certification, have not passed security audits, and require technical maintenance. To protect your accounts on a daily basis, a certified key is the right choice.
Real security keys from €25
There are FIDO2 certified options below €30. For most users who want to protect Gmail, social networks, or online banking, they are more than sufficient.
ChipNet FIDO2 Basic
Entry-level FIDO2 key. Compatible with the most common services. Good option to get started without spending much.
Thetis FIDO2 Security Key
Compatible with passkeys and major online services. Compact design with protective cap for the connector.
Security Key NFC
Yubico's entry-level option. Adds NFC so you can use it on your mobile without cables or adapters.
YubiKey 5 NFC
For users with more advanced needs. Adds support for SSH, OpenPGP, and passkey storage on the key itself.
Which one is right for you?
| Use case | Recommended option |
|---|---|
| Protect Gmail, social networks, and online banking | ChipNet or Thetis (~€25) |
| Also protect your mobile via NFC | Security Key NFC (~€35) |
| USB-C port (MacBook, modern laptop) | Security Key C NFC (~€35) |
| Developer — SSH, GitHub, OpenPGP | YubiKey 5 NFC (~€69) |
| Learn without spending | Raspberry Pi Pico + Pico Fido (DIY, no certification) |
Which YubiKey to buy depending on your device? Complete 2026 guide →
Frequently asked questions
Can a USB drive protect my Google or Instagram accounts?
No. To protect online accounts you need a key with a certified FIDO2 chip. A USB drive can only block local access to your computer with additional software, but it doesn't work as a second factor in web services.
What's the difference between a FIDO2 key and 2FA via SMS?
SMS can be intercepted using techniques like SIM swapping — someone convinces your carrier to transfer your number to them. A FIDO2 key doesn't transmit any code over the network: authentication is resolved with cryptography directly between the key and the service. It's much harder to attack.
Do I need two keys?
It is recommended. If you lose the only key you have registered, you could lose access to your accounts. The standard approach is to register two: one for daily use and another kept as a backup.
Does the key work on mobile?
Yes, models with NFC work by holding the key near the back of your mobile. You don't need adapters or cables. Compatible with Android and iOS on services that support FIDO2.
A USB is not a FIDO2 key
The difference is not software — it's hardware. A generic USB drive doesn't have a certified cryptographic chip and cannot protect your online accounts.
There are certified options from €25. For most users, ChipNet or Thetis are enough to get started. If you want NFC for your mobile, Yubico's Security Key NFC is the next step.
DIY projects like Pico Fido are interesting for learning, not for everyday use.
