Yes, and hardware support for encrypted RAM already exists: https://en.wikipedia.org/wiki/Trusted_execution_environment https://en.wikipedia.org/wiki/Trusted_e

Yes, and hardware support for encrypted RAM already exists: https://en.wikipedia.org/wiki/Trusted_execution_environment https://en.wikipedia.org/wiki/Trusted_execution_environment However, this will never be perfectly secure against backdoored RAM in a multitasking environment, because the memory access patterns alone leak information. Additionally, I don't think any of these systems support authenticated encryption, which means you could do things like corrupt branch targets and hope to land on a big NOP slide you control.