Extras and Usage

What LED colors mean

Color	Meaning
Green	Idle
Blue	Idle with button pressed
Orange	Registration or Authenticate Request waiting for button to be pressed
Light Blue	Registration or Authentication successful
Red	Error or keys wiping request pending which needs 5 button presses

Case for U2F Zero

I made a case that you can 3D print for a U2F Zero. See hardware/case.

Using the TRNG

You can access the U2F Zero's internal random number generator to get some high quality entropy.

# output
cd tools/u2f_zero_client
./client.py rng

# or seed 
./client.py seed < /dev/urandom

Resetting the key

This is only valid for older 1.0 version builds. 1.1 version and up support unlimited keys.

U2F Zero 1.0 has 15 slots to register services. You can delete all registered keys by running the following

cd tools/u2f_zero_client
./client.py wipe

The LED will turn red and after pressing the button 5 times, all the keys will be wiped. You cannot undo this.