After a long break, I’m back working on my FIDO2 authenticator! With BLE dropped from Chrome, I’ve shifted gears to USB—and that meant switching from ESP32 to STM32 (and soon RP2040). The latest prototype features a fingerprint scanner, secure element, and a fresh USB PCB. Still lots to build, but it’s moving again!

A lot of people asked if they can buy the URU Card—so I built one more, opened a little Tindie store, and… it sold out instantly. I’ll build more in small batches, so if you’re interested, just hit the watchlist and let me know your PCB color preference. No Kickstarter (yet), just a hobby!

While working on the URU Card project, I realized just how practical the credit card form factor really is—so I redesigned URU Key into URU Card Pro. It now fits in a wallet, runs on an ultra-thin Li-Ion battery, and includes a tiny OLED display for feedback. Same secure guts, much better usability!

Got a fresh batch of URU Card PCBs, and this time I used them to build a full hard shell case—just by stacking boards together. No 3D printing needed! I also switched to a PCB antenna (zero cost!) and prepped the layout for a future USB interface with the FT260 chip. It’s compact, wallet-friendly, and fully functional.

Finally, a working BLE-based FIDO2 authenticator on Arduino! The URU Card project now supports basic credential creation and authentication via ESP32. Still early-stage (with hardcoded keys for now), but it’s enough to pass WebAuthn tests in Windows—and it’s open for everyone to try and build on.

After a lot of requests to open-source URU Key, I’m starting a new project—URU Card! It’s a wallet-sized, open-source FIDO2 authenticator with an OLED screen, touch keyboard, and ESP32 brain. No biometrics (for now), but secure, DIY-friendly, and easy to build with Arduino libraries. Want to join in?

It’s been a while since the last URU Key update, but the project’s still alive and kicking! Chrome dropped BLE support (ouch), but Windows still plays nice. Plus, I got official docs from Fingerprint Cards (🎉), and even tested URU Key with Windows Hello. Oh—and a new open-source project is coming soon!

Hardware is done! After months of prototyping, I finally finished the compact 40×15mm URU Key device—complete with ESP32, fingerprint scanner, security chip, LiPo battery, and USB-C. It’s basically a fitness tracker… but for secure authentication. Now onto the software (and maybe a proper case 😅).

It’s official—URU Key is now a real, standalone device! I added the custom power board, used spring-loaded pins for easy firmware updates, and screwed everything together into a compact 35×20×10mm unit. Hardware’s basically done—now it’s time to dive deeper into the firmware, especially the biometric side.

Next step: power! I explored both CR2032 coin cells and tiny rechargeable LiPo batteries for the URU Auth device. Settled on a rechargeable setup with a TP4054 charger and USB-C—compact, convenient, and way more user-friendly. Bonus: added battery level monitoring and auto power-off to keep things efficient.

Everything’s finally coming together! I combined the ESP32, fingerprint scanner, and ATECC508A security chip into a single board—the first real version of my own FIDO2 Authenticator: URU Auth (You Are You). It’s handheld, it lights up, and it’s so close to being fully autonomous. Time to tackle power and fingerprint recognition!

The PCBs finally arrived—couldn’t resist jumping straight into assembly. Hot air soldering the ESP32 Pico D4 was a first for me, but surprisingly satisfying! The prototype is up and running, even on battery power. Now the real challenge begins: fingerprint scanning and matching. Let’s gooo!

Tried to go full DIY and desoldered the fingerprint sensor from the R300 module… but hit a wall—the pad layout doesn’t match any docs I could find 😕. So, switching gears: I’ve designed my own custom dev board for the authenticator with ESP32 Pico D4, ATECC508A, and room for a scanner. Boards are on the way!

Using a button for FIDO2 user verification felt… a bit too easy to spoof. So I grabbed two fingerprint modules—GROW R300 and FPC1020—to try adding real biometric authentication. R300 might even let me skip its built-in MCU and handle image processing myself. Let’s see where this goes!

After getting FIDO2 working on Android, I gave it a go on the ESP32. Started with Arduino, but switched to ESP-IDF for more control. It’s super stripped-down—only one in-memory credential and a button for user presence—but it works! Got both registration and login running. Video inside!

Spent a couple weekends deep-diving into a real FIDO2/WebAuthn implementation—and wow, it’s more complex than it looks. Ended up rebuilding the BLE GATT server on Android for better control. Got “Make Credential” working (video inside!), plus found a quirky Chrome spec mismatch along the way.

Spent the weekend turning an ESP32 into a FIDO2 BLE Authenticator! Chrome even recognizes it (though it doesn’t do much yet). Also found a neat secure chip—ATECC508A—that could store encrypted keys. Still brainstorming how to handle more than 16 keys. Nerdy fun!

Ever heard of logging in without passwords? I stumbled upon the FIDO2/WebAuthn standard and it’s actually pretty cool—just your fingerprint and you’re in. I looked into how it works, its pros, and some open questions that still bug me (like… what if you lose the device?). Check it out!