Signal is generally understood to be the best messaging app around. It uses a controversial new feature in Intel processors to prove that Signal isnt storing your contact info. The less Signal knows about you, the less any bad actor in the future can decipher from Signals information. Intel controls what the code says in the software in the processor, and the code in that enclave is signed with a unique key that Intel, not the computer’s owner, controls. Signal outlined how it plans to use SGX as a sort of middleman between its servers and your phone’s contacts, taking it one step further.”]
Source: https://gizmodo.com/signal-is-using-a-surprising-tool-to-make-your-privacy-1818820892