[mtgx]

They could probably still use this "design feature" (that Signal doesn't have) to hack users who don't authenticate the people they're talking with (also authentication isn't enabled by default on WhatsApp, but it is on Signal):

https://www.theguardian.com/technology/2017/jan/13/whatsapp-...

If you're a user of WhatsApp, make sure you enable the two-factor authentication PIN, too, because otherwise it should be relatively trivial for your own government to gain access to your account by using your number with the local carrier's help (it's also possible to do it without the carrier's help, given how broken the security of carrier networks is). Many Telegram users were hacked this way by the government in Russia, too.