iOS Secure Boot Chain & App Sandbox (2D)

Secure Boot Chain

Firmware

Stage

Idle

Boot result

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Boot ROM (immutable, factory-fused) verifies LLB, LLB verifies iBoot, iBoot verifies the kernel. Each stage checks the cryptographic signature of the next before running it — one broken link halts the boot.

App Sandbox

Direct cross-app read

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Permission API call

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Each app runs in its own sandboxed container and can only reach its own data. Reading another app's container directly is denied by the kernel; reaching camera/contacts/location data works only through an API that first asks the user for consent.

Verified / allowed Signature fail / blocked Idle / unverified