I think Mozilla is trustable (not being biased since I worked briefly there).<p>But to be fair:<p>&gt; This reasoning just doesn&#x27;t apply at all to open source software like Firefox.<p>This is not true. You can&#x27;t tell what is actually running on the server side, so the protocol must be able to handle the encryption on the client side and server never able to read the plaintext in the first place, and this is actually problematic for many products out there claiming &quot;oh our code is open source so you can trust us.&quot;