Trezor Safe 3/5/7 (hardware cold wallets)

[phnx]

Security Key Comparison

TROPIC01, or Trezor? If the latter, could you elaborate at Trezor Safe 3/5/7 (hardware cold wallets)? My line of thinking is that TROPIC01 was included as some neat additional defense-in-depth, but its compromise doesn’t compromise the security of the product below what anything else provides.

Tropic01 really, in the Trezor Safe 7 it’s not a huge deal since there is still the OPTIGA secure element, but then your effective security is the same as the Trezor Safe 3/5 leaving no reason to spend almost 2× as much on the Safe 7.

Where it would be more impactful would be any product where you only have one secure element, like anywhere you need a hardware root of trust, such as for IoT devices. Unfortunately, but perhaps unsurprisingly, having only just released their first product, Tropic Square are in my opinion not yet established enough to prove they have what it takes to build robust secure elements that stand up to intrusion attempts over time (like the Titan M2 for instance).

Security Key Comparison

Because it wouldn’t really make much sense to stop selling the Trezor Safe 7. With this vulnerability, an attacker with physical access, an expert skill level, and more than €30,000 worth of specialized equipment could extract TROPIC01’s secret contribution. The attacker would still have to compromise the second secure element. They would also have to compromise the STM32U5 protection layer and somehow obtain or brute-force the user’s PIN, which can be up to 50 digits. So, I don’t see how sc…

Thus I never said they should stop selling the Safe 7, but all their marketing is based on the Tropic01 being necessary because closed-source secure elements can’t be trusted when in fact the opposite is true in this case. There is at this time no reason to spend nearly 2× as much for the Safe 7 over the Safe 5.