But the &quot;observer&quot; can still know which mobile phone is yours and who communicates with whom? Especially if the &quot;observer&quot; has the info from the Signal servers.<p>Edit (as i can&#x27;t post you reply to your answer):<p>And based on the NSA principle of the &quot;thee levels of distance&quot; everybody is reachable as long as some common numbers are in our contact lists which we happily upload.