Just wondering, what additional security would you expect from open hardware vs. open software with transparently designed hardware? From a threat modeling perspective it seems that if the device is just using one chip onboard there are no clear security advantages of open hardware. Open hardware would only be provide a security benefit if you are planning to make your own security key, which most people won't be doing. And by being open hardware there is an additional threat model created where it is now easy for adversary to create identical clones of security key that can be used maliciously.