[teamhappy]

Nitrokey is open source (hardware and software). They claim the "installed firmware can be exported and verified, preventing attackers from inserting backdoors into products during shipping". (https://www.nitrokey.com/)

They list Google as one of their customers.

Also if you're a Linux kernel developer you get one for free: https://www.nitrokey.com/news/2018/nitrokey-partners-linux-f...