\HeadingLevelB{Protection Boundaries}
\label{sec:protection_boundaries}

Sanctum's isolation protects the privacy and integrity of an enclave's
software, even in the face of a malicious operating system. Sanctum improves upon SGX
by isolating cache sets and page tables used to access an enclave's private
memory, as well as microarchitectural state updated as a side effect of enclave execution.
The improved isolation defeats attacks that exploit the memory access
pattern information leaks that result from cache and page table sharing, as well as attacks attempting to infer private control flow information from observing core state after enclave execution.
