[password4321]

Signal Private Messenger built private contact discovery and secure value recovery using Intel Software Guard eXtensions (SGX), similar to AMD Secure Memory Encryption (both usually used for DRM).

https://signal.org/blog/private-contact-discovery/ (2017) https://signal.org/blog/secure-value-recovery/ (2019)

Intel SGX is mostly orthogonal to Intel IME but each is an additional attack surface with enough privilege/persistence to assist attacks on the other.