I never said they are cheap or cheapest wallet in the world, but they are certainly airgapped open source devices with fair price.
Keystone is not open source, and I have been considering writing a blog posts that dives into their claims.
Here's their 5 GB+ Android OS that does not have source code available:
https://github.com/KeystoneHQ/Keystone-systemDue to copyright, some vendors’ code cannot be made public, and we have removed some of the code from the source code. Therefore this open source code cannot be compiled. However, we can share this part of code under an NDA if you want to fully verify the code and reproduce it. Please send an email to
eng@keyst.one. Since the size of a single repo on github cannot exceed 5G, we put the code on AWS. You can access the code through this link: keystone-system
What about their secure element firmware? Looks like that code can only be compiled with proprietary ARM software called Keil.
https://github.com/KeystoneHQ/keystone-se-firmware Additionally, there is no information as to who even makes their secure element. It's some kind of white labeled processor.
https://github.com/KeystoneHQ/Keystone-developer-hub/blob/main/hardware/Keystone_V1.02_BOM.xls Furthermore, their hardware schematic is not all-inclusive and omits the self-destruct mechanism.
Hopefully Keystone 3 will actually be open source, but I am growing tired of hardware wallet companies hiding behind false claims of open source. It really damages the definition and I consider it attack on the FOSS movement.