[quote='797344022, fxk510, /thread/760541?answerId=797344022#797344022, /profile/fxk510'] And I assume by general-purpose signing from 3rd party code you mean that Apple code might be able to do it, but we will not be able to accomplish it? [/quote] Yes, but that “general-purpose” rider is important. The key thing here is the “it” in the above quote. By “general-purpose” I’m talking about calling APIs, like SecKeyCreateSignature and Apple CryptoKit, that allow you to sign arbitrary data. Beyond that, for example, in the Platform SSO stuff, things get more nuanced. [quote='797411022, fxk510, /thread/760541?answerId=797411022#797411022, /profile/fxk510'] would an ACME certificate, which can be hardware bound, be used during the system context prior to login? [/quote] I don’t think so. I don’t know a lot about ACME, but it seems to me that they must be issued to the machine or the user. If they’re issued to the user, you can’t use them prior to login because the user’s keychain is locked. If th