This is called secure, <i>multi-party</i> computation. Secure computation, which can be just one party, would take a lot longer to explain. It&#x27;s also a prerequisite for secure, multi-party computation as attacks on the host can bypass the multi-party protocol. That&#x27;s why you&#x27;ll always see me mock those that think such schemes will let us ignore INFOSEC problems. They&#x27;re fun to read, though.