OpenSK is written in Rust and runs on TockOS to provide better security. It is designed to be used by researchers, security key manufacturers, and to help develop innovative features and accelerate security key adoption. You can make your own key by flashing the OpenSK firmware on a computer with a special version of the software. The software is now available to download and use for the first time in the U.S. and Europe for $1,000 ($2,000) version of OpenSK.”]
Source: https://security.googleblog.com/2020/01/say-hello-to-opensk-fully-open-source.html