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Is it worth trying to move my friends from WhatsApp to Signal? As I understand it, they're both e2e encrypted. I'm also trying to move my chats from SMS and Gc

Is it worth trying to move my friends from WhatsApp to Signal? As I understand it, they're both e2e encrypted. I'm also trying to move my chats from SMS and Gchat to something encrypted, but am torn between WhatsApp and Signal. The former has more of a buy-in with my contacts already. I realize WhatsApp is owned by Facebook, but isn't the whole point of e2e encryption that you don't have to trust the intermediate infrastructure? And if you enable the setting to warn if the key changes, there's no danger, right?

kasey_junk 6y ago
The metadata is the difference. Your contact graph is fair game on WhatsApp for Facebook
- jwr 6y ago
  Exactly! And it was worth $19 billion to Facebook. That's what they paid to acquire WhatsApp, one would suppose not with the goal of watching encrypted messages fly by.
Skunkleton 6y ago
That is an impossible question to give one answer to. There are lots of considerations. For example: 1) Do you trust facebook with messaging metadata? For example, do you want them to know that you messaged your friend Jane a specific number of times on specific dates, knowing that they can coorelate this information to facebook profiles, and will give up this information for ad, and law enforcement purposes. 2) Do you trust Signal's infrastructure to be reliable when you need it? 3) What is you're threat model? For me, I want to be kept out of all ad-related data sets, and I want to have conversations with friends without having to think about a paper trail. 4) Do you care that you will have to convince people to install yet another messaging app? 5) Do you trust that Signal and WhatsApp have correctly integrated the underlying crypto protocol? I assume that you would, considering its history. Still, I would trust signal more in this regard. 6) Do you think that Facebook or Signal is more likely to cut a privacy corner in support of a ease-of-use feature? Do you care? For my friends, the answer is that I use signal. Everyone who doesn't use signal falls back to getting SMS, or phone calls. The problem here is that SMS and phone calls are both huge privacy holes. For my threat model, I don't care, but you might.
rampant_ai 6y ago
> isn't the whole point of e2e encryption that you don't have to trust the intermediate infrastructure If the client app is open source. There's no way to know FB isn't just copying your keys or doing something else nasty. That whole spiel on their site about how E2EE protects you/makes the world a better place/yada yada is completely moot since they use a closed-source client.
Legogris 6y ago
This post has a lot of good context to nuance the dynamics on WhatsApp message confidentiality: https://makensi.es/privacy/e2ee/2020/03/23/can-facebook-read-whatsapp.html#badcontext https://makensi.es/privacy/e2ee/2020/03/23/can-facebook-read... There are specifically two points that make me not confident in WhatsApp keeping my messages secure: * I don't have time to dig out a good source for it right now, but I remember seeing a credible claim that they already have in-place a mechanism to instruct the client app send back cleartext messages to a server. If they do not, it would be trivial to add it in an update. * The client will keep nagging you to enable cloud backups of message history. If you our your counterparty does this, message history is stored in cleartext on one of the major cloud providers. Are you confident that the person you're talking to hasn't enabled this, maybe even by mistake?
jwr 6y ago
> As I understand it, they're both e2e encrypted The important distinction here is that WhatsApp uploads your entire contact book to Facebook. They have up-to-date information on your entire real-life social graph (including people who are not on Facebook and/or never shared their phone with Facebook) and the groups you belong to. If you don't believe me, request a copy of your data in WhatsApp and see for yourself. So, by using WhatsApp, you are basically snitching on your friends and uploading their data. Think about the implications — one day, you or one of your friends will add a phone number to Facebook (of course, "for security purposes only, to recover your account". From that moment, Facebook will be able to link an online identity to an offline one, and mine a trove of data: friends, groups, locations. If you want a different way of looking at it, Facebook paid $19 billion for WhatsApp. That's how much it was worth to them. You don't spend 19 billion dollars just to watch e2e encrypted messages fly by. I admire the way WhatsApp markets itself as the "encrypted" communications app, somehow hiding the whole problem with groups and contacts as insignificant. Another frequently seen spin is on Signal: that it "only hashes" the phone numbers and that it's "effectively the same thing". Good PR moves, both.
- Gaelan 6y ago
  It is possible to use WhatsApp (on iOS, at least) without giving it contact access. I do this and it isn't too bad—you still see people's WhatsApp nicknames, so it's not like you're just looking at phone numbers. Of course, that does nothing to stop them from tracking who you actively communicate with.
Aachen 6y ago
WhatsApp is opportunistic encryption by default, trusting the server to provide it keys. Pretty much nobody turns on showing when someone's key changes, and if you do and you verified each 's keys, the server can still learn the plaintext of at least one message by changing keys right when you send a message. Which is a very tiny risk, but it's just not what one would expect. It's as if your browser would continue loading a page with an invalid HTTPS certificate and show you a warning afterwards -- and only if you turned on showing that warning in the settings. Even if you turn it on and you're not afraid of the server swapping the key when you send a message (which is fair enough), do all your contacts also have it turned on? And would they tell you immediately and out of band (otherwise the attacker can suppress or change the message) that they saw your key change? But an even bigger reason I don't have whatsapp is because of Facebook. Metadata has already been mentioned by others so I won't repeat that.

kasey_junk 6y ago

The metadata is the difference. Your contact graph is fair game on WhatsApp for Facebook

jwr 6y ago
Exactly! And it was worth $19 billion to Facebook. That's what they paid to acquire WhatsApp, one would suppose not with the goal of watching encrypted messages fly by.

Skunkleton 6y ago

That is an impossible question to give one answer to. There are lots of considerations. For example: 1) Do you trust facebook with messaging metadata? For example, do you want them to know that you messaged your friend Jane a specific number of times on specific dates, knowing that they can coorelate this information to facebook profiles, and will give up this information for ad, and law enforcement purposes. 2) Do you trust Signal's infrastructure to be reliable when you need it? 3) What is you're threat model? For me, I want to be kept out of all ad-related data sets, and I want to have conversations with friends without having to think about a paper trail. 4) Do you care that you will have to convince people to install yet another messaging app? 5) Do you trust that Signal and WhatsApp have correctly integrated the underlying crypto protocol? I assume that you would, considering its history. Still, I would trust signal more in this regard. 6) Do you think that Facebook or Signal is more likely to cut a privacy corner in support of a ease-of-use feature? Do you care? For my friends, the answer is that I use signal. Everyone who doesn't use signal falls back to getting SMS, or phone calls. The problem here is that SMS and phone calls are both huge privacy holes. For my threat model, I don't care, but you might.

rampant_ai 6y ago

> isn't the whole point of e2e encryption that you don't have to trust the intermediate infrastructure If the client app is open source. There's no way to know FB isn't just copying your keys or doing something else nasty. That whole spiel on their site about how E2EE protects you/makes the world a better place/yada yada is completely moot since they use a closed-source client.

Legogris 6y ago

This post has a lot of good context to nuance the dynamics on WhatsApp message confidentiality: https://makensi.es/privacy/e2ee/2020/03/23/can-facebook-read-whatsapp.html#badcontext https://makensi.es/privacy/e2ee/2020/03/23/can-facebook-read... There are specifically two points that make me not confident in WhatsApp keeping my messages secure: * I don't have time to dig out a good source for it right now, but I remember seeing a credible claim that they already have in-place a mechanism to instruct the client app send back cleartext messages to a server. If they do not, it would be trivial to add it in an update. * The client will keep nagging you to enable cloud backups of message history. If you our your counterparty does this, message history is stored in cleartext on one of the major cloud providers. Are you confident that the person you're talking to hasn't enabled this, maybe even by mistake?

jwr 6y ago

> As I understand it, they're both e2e encrypted The important distinction here is that WhatsApp uploads your entire contact book to Facebook. They have up-to-date information on your entire real-life social graph (including people who are not on Facebook and/or never shared their phone with Facebook) and the groups you belong to. If you don't believe me, request a copy of your data in WhatsApp and see for yourself. So, by using WhatsApp, you are basically snitching on your friends and uploading their data. Think about the implications — one day, you or one of your friends will add a phone number to Facebook (of course, "for security purposes only, to recover your account". From that moment, Facebook will be able to link an online identity to an offline one, and mine a trove of data: friends, groups, locations. If you want a different way of looking at it, Facebook paid $19 billion for WhatsApp. That's how much it was worth to them. You don't spend 19 billion dollars just to watch e2e encrypted messages fly by. I admire the way WhatsApp markets itself as the "encrypted" communications app, somehow hiding the whole problem with groups and contacts as insignificant. Another frequently seen spin is on Signal: that it "only hashes" the phone numbers and that it's "effectively the same thing". Good PR moves, both.

Gaelan 6y ago
It is possible to use WhatsApp (on iOS, at least) without giving it contact access. I do this and it isn't too bad—you still see people's WhatsApp nicknames, so it's not like you're just looking at phone numbers. Of course, that does nothing to stop them from tracking who you actively communicate with.

Aachen 6y ago

WhatsApp is opportunistic encryption by default, trusting the server to provide it keys. Pretty much nobody turns on showing when someone's key changes, and if you do and you verified each 's keys, the server can still learn the plaintext of at least one message by changing keys right when you send a message. Which is a very tiny risk, but it's just not what one would expect. It's as if your browser would continue loading a page with an invalid HTTPS certificate and show you a warning afterwards -- and only if you turned on showing that warning in the settings. Even if you turn it on and you're not afraid of the server swapping the key when you send a message (which is fair enough), do all your contacts also have it turned on? And would they tell you immediately and out of band (otherwise the attacker can suppress or change the message) that they saw your key change? But an even bigger reason I don't have whatsapp is because of Facebook. Metadata has already been mentioned by others so I won't repeat that.