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WhatsApp claims that its calls are end-to-end encrypted: https://faq.whatsapp.com/en/android/28030015/ https://faq.whatsapp.com/en/android/28030015/ As does Ri

WhatsApp claims that its calls are end-to-end encrypted: https://faq.whatsapp.com/en/android/28030015/ https://faq.whatsapp.com/en/android/28030015/ As does Riot.im (I think? Can't find any explicit mention of calls being encrypted): https://about.riot.im/features.html https://about.riot.im/features.html Can someone with more expertise comment on these two? (I understand that because WhatsApp isn't F/LOSS, there's a lot that we can't know about how it works).

fwn 7y ago
I'm using Google Duo a lot and (to my surprise) it claims to be end-to-end encrypted: https://support.google.com/duo/answer/9280240?hl=en https://support.google.com/duo/answer/9280240?hl=en I started to use it as an alternative to WhatsApp calls for their superior call quality. Many people already have it without knowing about it. AFAIK that's due to being preinstalled on newer devices or being available as an instant app(?) That does seem to imply that you don't have to actively install it to work? ... but I'm not sure.
amiraliakbari 7y ago
Riot (Matrix to be precise) only supports E2E encryption for one to one calls. Group calls are handled by a Jitsi backend and are unavailable in E2E encrypted conversations with more than two members.
kelnage 7y ago
My understanding of how these E2E products often do their (video) call encryption is not that they use a clever communication protocol like the one used in Signal to protect each frame/packet (which would likely introduce huge amounts of delay - not a good user experience!). Instead during call initiation, they do the key negotiation/sharing over the same messaging protocol they use to transmit their normal messages; i.e. effectively they generate the call encryption key on the device, send it as a E2E encrypted message to the call recipient(s), and use the standard call encryption methods (probably based on SRTP?) to actually protect the call. Thus, assuming the call encryption methods work correctly (which I have no immediate reason to believe they don't), for an adversary to obtain the key (and decrypt the call), they would need to break the E2E encryption used to transmit the messages; therefore the call is E2E encrypted.
jillesvangurp 7y ago
It's very simple, the vast majority of popular chat applications out there don't have open source backends. Which means we basically have to trust their owners to do the right things and hope for the best. The business model of choice in this space is to (sometimes) have partially open source clients but almost never use OSS in the backend. There's a lot of secret sauce and magic that these companies use to differentiate from each other and most of that is proprietary. This provides these companies with a control point to lock in their users to their network. For the same reason attempts at standardization of protocols and federating chats and calls between networks have largely stalled/failed. XMPP is technically still around; it's just that none of the popular solutions in this space use it. I'd say Signal is the positive exception in this space where both server and client are OSS and the client UX is pretty decent. Telegram talks a lot about security as well but their OSS seems limited to mostly client side. Of course a lot of the crypto is client side so depending on how paranoid you are that may or may not be good enough. Either way there probably is a lot of server side stuff that is relevant to end to end security that is not being scrutinized outside Telegram. For both, even if the client is OSS, what goes into the app stores may still include stuff not accounted for in the source code. Auditing the source code and the binaries are two things. And then there's the runtime environment to consider, which is a OS that is probably proprietary that includes lots of stuff that is a bit icky from a security point of view. So, there's multiple levels of "trust us, we know what we are doing" that you'd have to buy into in order to feel secure. IMHO that has been a problem for a while but most people/companies seem to be indifferent when it comes to security and happily pay through their nose for 100% proprietary security snake oil peddled by the sales people of e.g. MS, Zoom, Slack, etc.
- Aachen 7y ago
  > the vast majority of popular chat applications out there don't have open source backends. Which means we basically have to trust their owners to do the right things and hope for the best. Err, if that were the case, then why do we bother with encryption at all? End to end encryption means you don't need to trust the owners, at least for message contents. For metadata, yeah, that's why I choose not to use a known-bad company like Facebook (i.e. WhatsApp) and would rather use Signal or Wire and hope for the best, but that's only metadata. Doesn't mean I trust Wire with the contents of my communication, at least when verifying people's keys.
hiq 7y ago
WhatsApp calls are limited to 4 parties or so, which is a deal-breaker for a lot of people.
- Aachen 7y ago
  Wire's video calls are also limited to 4 people. I think it's a client-side limit, but with 4 our laptops/phones already struggle so it seems to be a sensible limit. Audio calls can be with more people, at least six but I don't know how many. I guess such are the limitations of encryption currently, at least when one wants to have browser support instead of native code and wants to support mobile systems.
ezg 7y ago
WhatsApp is owned by a company in the business of collecting metadata so I don't trust them as far as I can throw them. Even if the call is E2E, your address book is uploaded directly to their server.

fwn 7y ago

I'm using Google Duo a lot and (to my surprise) it claims to be end-to-end encrypted: https://support.google.com/duo/answer/9280240?hl=en https://support.google.com/duo/answer/9280240?hl=en I started to use it as an alternative to WhatsApp calls for their superior call quality. Many people already have it without knowing about it. AFAIK that's due to being preinstalled on newer devices or being available as an instant app(?) That does seem to imply that you don't have to actively install it to work? ... but I'm not sure.

amiraliakbari 7y ago

Riot (Matrix to be precise) only supports E2E encryption for one to one calls. Group calls are handled by a Jitsi backend and are unavailable in E2E encrypted conversations with more than two members.

kelnage 7y ago

My understanding of how these E2E products often do their (video) call encryption is not that they use a clever communication protocol like the one used in Signal to protect each frame/packet (which would likely introduce huge amounts of delay - not a good user experience!). Instead during call initiation, they do the key negotiation/sharing over the same messaging protocol they use to transmit their normal messages; i.e. effectively they generate the call encryption key on the device, send it as a E2E encrypted message to the call recipient(s), and use the standard call encryption methods (probably based on SRTP?) to actually protect the call. Thus, assuming the call encryption methods work correctly (which I have no immediate reason to believe they don't), for an adversary to obtain the key (and decrypt the call), they would need to break the E2E encryption used to transmit the messages; therefore the call is E2E encrypted.

jillesvangurp 7y ago

It's very simple, the vast majority of popular chat applications out there don't have open source backends. Which means we basically have to trust their owners to do the right things and hope for the best. The business model of choice in this space is to (sometimes) have partially open source clients but almost never use OSS in the backend. There's a lot of secret sauce and magic that these companies use to differentiate from each other and most of that is proprietary. This provides these companies with a control point to lock in their users to their network. For the same reason attempts at standardization of protocols and federating chats and calls between networks have largely stalled/failed. XMPP is technically still around; it's just that none of the popular solutions in this space use it. I'd say Signal is the positive exception in this space where both server and client are OSS and the client UX is pretty decent. Telegram talks a lot about security as well but their OSS seems limited to mostly client side. Of course a lot of the crypto is client side so depending on how paranoid you are that may or may not be good enough. Either way there probably is a lot of server side stuff that is relevant to end to end security that is not being scrutinized outside Telegram. For both, even if the client is OSS, what goes into the app stores may still include stuff not accounted for in the source code. Auditing the source code and the binaries are two things. And then there's the runtime environment to consider, which is a OS that is probably proprietary that includes lots of stuff that is a bit icky from a security point of view. So, there's multiple levels of "trust us, we know what we are doing" that you'd have to buy into in order to feel secure. IMHO that has been a problem for a while but most people/companies seem to be indifferent when it comes to security and happily pay through their nose for 100% proprietary security snake oil peddled by the sales people of e.g. MS, Zoom, Slack, etc.

Aachen 7y ago
> the vast majority of popular chat applications out there don't have open source backends. Which means we basically have to trust their owners to do the right things and hope for the best. Err, if that were the case, then why do we bother with encryption at all? End to end encryption means you don't need to trust the owners, at least for message contents. For metadata, yeah, that's why I choose not to use a known-bad company like Facebook (i.e. WhatsApp) and would rather use Signal or Wire and hope for the best, but that's only metadata. Doesn't mean I trust Wire with the contents of my communication, at least when verifying people's keys.

hiq 7y ago

WhatsApp calls are limited to 4 parties or so, which is a deal-breaker for a lot of people.

Aachen 7y ago
Wire's video calls are also limited to 4 people. I think it's a client-side limit, but with 4 our laptops/phones already struggle so it seems to be a sensible limit. Audio calls can be with more people, at least six but I don't know how many. I guess such are the limitations of encryption currently, at least when one wants to have browser support instead of native code and wants to support mobile systems.

ezg 7y ago

WhatsApp is owned by a company in the business of collecting metadata so I don't trust them as far as I can throw them. Even if the call is E2E, your address book is uploaded directly to their server.