Intel SGX

Intel SGX secures sensitive data in-use by isolating code and information within hardware-encrypted CPU enclaves.

Intel Software Guard Extensions (SGX) provides hardware-level isolation for sensitive workloads through secure memory partitions called enclaves. These enclaves reside in the Processor Reserved Memory (PRM): a dedicated slice of RAM encrypted at the hardware level. Because the CPU handles encryption, data remains protected even if the operating system or hypervisor is fully compromised. Developers use the Intel SGX SDK to split applications into trusted and untrusted components. Major implementations include Signal (for private contact discovery) and Microsoft Azure (Confidential Computing series). It successfully shrinks the attack surface to the processor and the specific code inside the enclave.

https://www.intel.com/content/www/us/en/architecture-and-technology/software-guard-extensions.html