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What apple calls Secure Element is a separate chip that essentially is an eSIM with NFC interface (or in other words, smart card MCU with larger memory and more
by dfox 4y ago
What apple calls Secure Element is a separate chip that essentially is an eSIM with NFC interface (or in other words, smart card MCU with larger memory and more IO). Apple's implementation of what TrustZone is supposed to solve is called Secure Enclave and also involves separate CPU core (inside the application SoC) that is isolated from the application cores by how the hierarchy of various buses on the chip is structured.
I assume that there are two reasons why it is done this way instead of software/weird-CPU-state solutions (like TrustZone): this construction is easier to reason about and at least in the Secure Element case easier to certify to the requirements of card issuers (as it is essentially standard off-the-shelf secure MCU).
- jeroenhd 4y agoI agree that a separate secure chip is a superior option to TrustZone. However, if TrustZone is good enough for authorising bank transfers, it's also good enough for me. Security chips have also had their vulnerabilities over the years, through power injection attacks or similar, that allow cloning just like bypassing the security of TrustZone would. The attack may be harder to pull off, but nothing is unhackable.