Contrarian take - Ledger is more secure than Coldcard.
There are no guarantees than the open-source is actually compiled on a the MCU chip.
The chip secuity infrastucture of BitBox might be the best, but I just don’t like it and it feels like there are some unknown risks of combining both MCU & secure chip for unlocking seed.
PS. I use Coldcard because of air gap, but might switch back. The only thing I hate is that there is no #Bitcoin only Ledger :/
Makes no sense, there is no other place for the code, maybe would compile in the USB connector? 😆
You can actually prove it does what it claims for reproducibly build it yourself https://github.com/coldcard/firmware
here are some folks doing just that https://bitcoinbinary.org/
I am still doing research on this and realized I had one major false assumption - that CC runs on MCU chip with no SE. Lol, the Mk4 has 2 of those 😅
I think I assumed it as I have heard CoinKite guys saying on podcasts that everything is open-source. SE’s can’t be due to NDA so I assumed they have only MCU.
At least I learnt a lot today.
This has a good overview https://blog.coinkite.com/understanding-mk4-security-model/
