The coordinator app generates a QR code from the unsigned transaction for the hardware wallet to sign. The hardware wallet generates another QR code with the signature.
If the hardware wallet has been hacked to change the data in any way, the coordinator app won't accept the signature, because the signature won't be mathematically correct for the transaction on the coordinator app.
That's a really important concept to understand.
The Bitcoin blockchain is susceptible to key leakage via the OP RETURN field and a narrowband subliminal channel based on brute-forcing the random factor of the signature scheme.
That's a really important concept to understand.
https://www.annessi.net/data/2018-subliminalblockchain_preprint.pdfYou seem to be worried about a threat that is so minor that it's not worth thinking about.
Governments do not have to bother with tampering with chips and putting in some back doors and 1000s of other things.
Their are quicker and easier ways to do things.
In the real cost of running a government if any of them truly wanted to disrupt crypto and make people loose faith and money in it till is disappeared there are dozens of cheaper / faster / easier ways to do it then having James Bond sneak into an engineers lab and change chip design to implement a vulnerability that may or may not wind up in a device that people use to secure
BTC / crypto.
-Dave