A Trezor is a mini computer keeping access to the seed contained to an isolated component with on-device display / confirmation. It's wrong to expect that an attacker with physical access won't be able to extract the seed. That remains true with an obfuscated secure element too.
Conversation
The BIP39 passphrase feature (passphrase appended to the seed phrase before key derivation) is the fundamental defense against an attacker gaining physical access. Trezor Model T has a much better implementation than the original by supporting on-device entry of the passphrase.
1
2
11
An attacker with physical access can extract data stored on a device. Secure elements can make data extraction more expensive but it's still possible. The benefit of dedicated hardware wallets is isolating access to the seed/passphrase for orders of magnitude less attack surface.
2
1
8
Replying to
Although I absolutely agree nothing is 100% secure, a good secure element should be way towards the 'impossible' end of the feasibility spectrum. Unfortunately, it's often the app code that's an issue, not the HW.
1
Replying to
What's a good secure element making data extraction with physical access infeasible or extremely difficult / expensive? I don't think making it beyond the means of an independent security researcher with very limited resources and time to dedicate to it is a big success story.
Replying to
Most of the ones in your credit cards. They get tested for physical probe attacks, EM and optical glitching, SCA using both templates and ML methods, FBBA voltage bias attacks ... They're pretty robust all round, assuming the internal code is up to scratch.
1
Replying to
Yet the data can still be extracted in a lab, and with Bitcoin there's the required motivation to do it since the money can't just be returned or easily tracked. They can clean it through mixers / exchanges and end up with the money. It's useful, but it's not a magic solution.
2
Show replies