Or, at the very least, they can. Recently I got a friend to finally join me on Signal. He asked something about whether or not Signal is truly secure and private, like if it was safe from US government surveillance. I told him: “Well, it’s end-to-end encrypted, so they don’t know what we’re talking about, but they definitely know that we’re talking to each other.” I said that because Signal uses our phone numbers as ID’s. So, Signal would know that Phone Number A is talking to Phone Number B, an...