Local-only memory (say readable only from a certain CPU security ring and securely erasable in an atomic operation) is a useful tool for methods such as you des

Local-only memory (say readable only from a certain CPU security ring and securely erasable in an atomic operation) is a useful tool for methods such as you describe. What I'm shooting at is private memory under cryptographic control of a remote networked entity. I should more properly have said "remotely secured enclave" or something like that. I think in this area it's hard to be precise amidst confusion about who does the encryption, who generates and keeps the private keys, and what power that affords them.