OP presents SEs as green/good and lack thereof as red/bad. I agree that there is certain situations where a SE can save the day but equally does the SE with their NDA-requirement and secrecy lead to a situation where we trust a black box a whole lot for being our own bank and throw "don't trust - verify" too easily over board.
Especially hardware wallets that use their SE's TRNG as sole source of entropy should be called out! Nobody can prove the TRNG to be truly random and in the worst case it just creates hash("you won't guess this", serialNumber, sequenceNumber) "random" numbers that the inventor can trivially guess. Such a hardware wallet would allow the provider to know all the private keys generated by all the users, putting him in the position of being able to pull the rug at any time.
Please add in the OP:
- Is a single TRNG the sole source of entropy?
- Can the used entropy be audited or does the chip that mungs together all entropy spit out a master seed without accountability?
- Does the MCU trust the SE? To my understanding, BitBox02 does not entrust the SE even to hold the master seed. It only holds a symmetric key to decrypt the master seed stored outside the SE.
As you can see in my footer, I work on WalletScrutiny where my primary goal is to prevent rug pulls as I see them as a systemic risk if we get another MtGox situation where half the community is affected. Reliance on a compromised TRNG is one of my big concerns.