<i>Apple is required to have backdoors, at least on iPhones sold in foreign countries, isn&#x27;t it?</i><p>I don&#x27;t believe this is the case.<p><i>Even if the SE were completely secure, a rogue update of iOS could intercept the fingerprint or passcode whenever it is typed, and replay it to unlock the SE when spies ask for it. As far as I know, the on-screen keyboard is controlled by software which isn&#x27;t in the SE.</i><p>What you say about an on-screen passcode is likely true but the architecture of the secure enclave is such that the touch ID sensor is communicating over an encrypted serial bus directly with the SE and not iOS itself. It assumes that the iOS image is not trustworthy.<p>From the white paper [1]:<p><i>It provides all cryptographic operations for Data Protection key management and maintains the integrity of Data Protection even if the kernel has been compromised.<p>...<p>The Secure Enclave is responsible for processing fingerprint data from the Touch ID sensor, determining if there is a match against registered fingerprints, and then enabling access or purchases on behalf of the user. Communication between the processor and the Touch ID sensor takes place over a serial peripheral interface
bus. The processor forwards the data to the Secure Enclave but cannot read it. It’s encrypted and authenticated with a session key that is negotiated using the device’s shared key that is provisioned for the Touch ID sensor and the Secure Enclave. The session key exchange uses AES key wrapping with both sides providing a random key that establishes the session key and uses AES-CCM transport encryption.</i><p>[1]: <a href="https:&#x2F;&#x2F;www.apple.com&#x2F;business&#x2F;docs&#x2F;iOS_Security_Guide.pdf" rel="nofollow">https:&#x2F;&#x2F;www.apple.com&#x2F;business&#x2F;docs&#x2F;iOS_Security_Guide.pdf</a>