4 ms·

I've never understood why Slack can't add support for E2E encryption. I'm 100% positive they've got large clients demanding this functionality.

sroussey 7y ago
Probably how they do search.
- quotemstr 7y ago
  Just let each client index locally
  - s_kilk 7y ago
    How big is your hard drive? How about on your phone? I guess there's also the problem of how to let a new joiner view previous messages. Can that be done with e2e encryption?
    - vbezhenar 7y ago
      > How big is your hard drive? 512 GB > How about on your phone? 256 GB > I guess there's also the problem of how to let a new joiner view previous messages. Can that be done with e2e encryption? Of course. Share the key with a new joiner. Probably should be an option for admin, whether he wants to share (share the key) or does not want to share (generate new key and use it since that moment, old clients still remember old keys and can decrypt things).
      - madeofpalk 7y ago
        A single, shared key? Granted, I don't know much about encryption, end-to-end messaging, or otherwise, but it seems like a Very Hard Problem to solve for something like Slack.
        vbezhenar 7y ago
        > A single, shared key? Yes, shared among participants. > it seems like a Very Hard Problem to solve for something like Slack. There are plenty of messengers with E2E encryption and group chats with working search. Sure, it's not a straightforward task and server-side handling of search and other functions makes everything much easier, but I don't think that it's impossible task. Though I'm not sure if demand is big enough. I would think that just self-hosting slack would be preferable for many organizations.
        madeofpalk 7y ago
        > Yes, shared among participants. Honest question - how does this work across thousands of employees, some of which are almost guaranteed to be bad-actors at one point? Or is that just not a problem that's trying to be solved? What are the impacts if someone leaks that? > There are plenty of messengers with E2E encryption and group chats with working search. I don't know - are they on the (user) scale of Slack? How many people can you add to a group in WhatsApp or iMessage? (I honestly don't know, but I would suspect Slack lets you have more people in a 'group' than them). Again, I have only a very cursory knowledge of how iMessage does E2E encryption. Obviously Slack would need to choose a different approach, but I wouldn't look at other messaging apps for examples.
    - johannes1234321 7y ago
      Yes, that could be done with e2e encryption. Typically a setup would use one secret key for crypting one (set of) message(s) and that key would be encrypted in a way that all authorized users can decrypt it. A new user then only needs access to the group key, which can be done cheaply (by anybody with access to the group key and all user's public keys)
    - ben_w 7y ago
      Unless the channels you’re on amount to at least one Bible-length document per day and you’re trying to index multiple years of content, the storage requirements for an index aren’t going to be a problem.
    - deadbunny 7y ago
      Not easily.
  - thinkmassive 7y ago
    This seems to be how Matrix/Riot plan to enable search in E2E rooms: - https://github.com/matrix-org/matrix-search - https://github.com/vector-im/riot-web/issues/2548
  - beatgammit 7y ago
    So, is each web client going to download the full history so it can build an index? I like being able to login from anywhere, but building a local index could take some time, and I definitely don't want that to happen when I first open slack in the browser.
    - quotemstr 7y ago
      That's what local storage is for.
ltbarcly3 7y ago
They could, but I don't think it would really add much benefit. One of the main features of Slack vs IRC is that Slack has persistent and consistent chat history. If you look at apps like Signal, when you log on from a new device your history isn't available, because of the end to end encryption used to store the messages. To view the history you would have to be able to decrypt it, but that means there has to be some mechanism for users joining a channel for the first time to decrypt the history of that channel (unless you want to break that functionality). Unless there is some really neat cryptography trick I'm not aware of, that would mean you can't have end to end encryption where each user's data is encrypted in a way that is opaque to everyone except user(s) in the chat like Signal or Telegram. Now I guess you could set up some kind of broker system and have like a different encryption key per channel or per conversation or something, which would at least mean some hacker has to get both the archived chats as well as the keys. This would make stealing chat histories more complicated, but not less possible.
- yoz-y 7y ago
  In iMessage this was possible but all combinations of pairs of your devices had their own keys. When a new device was added you needed to allow it from a device already registered and they would then sync messages device-to-device. This has resulted in quite a lot of mangled histories. Now with iMessage in iCloud, I do not know how the E2E encryption is done.
  - konspence 7y ago
    >Now with iMessage in iCloud, I do not know how the E2E encryption is done It isn't done. Apple holds the master keys. The trust is that the iCloud server is not compromised.
    - yoz-y 7y ago
      I've read some discussions and key base articles and it seems that at least the master key is encrypted using your pin code. Not much, but I guess one could use a complex password.
leppr 7y ago
A read over Keybase's blog [1] makes one realize how non-trivial building a secure team chat is. We're still at a point in time where 99% of communities are ready to make exactly 0 compromise for privacy over usability. Slack is catering to the 99%. [1]: https://keybase.io/blog https://keybase.io/blog
fencepost 7y ago
Define "end." If one definition includes "the server(s)" then I'm positive it does at least on their Enterprise product, which notably last time I looked was the only one that could be considered HIPAA-compliant, aka "no your two - site medical practice can't use Slack to chat between the sites and coordinate anything involving patients."

sroussey 7y ago

Probably how they do search.

quotemstr 7y ago
Just let each client index locally
- s_kilk 7y ago
  How big is your hard drive? How about on your phone? I guess there's also the problem of how to let a new joiner view previous messages. Can that be done with e2e encryption?
  - vbezhenar 7y ago
    > How big is your hard drive? 512 GB > How about on your phone? 256 GB > I guess there's also the problem of how to let a new joiner view previous messages. Can that be done with e2e encryption? Of course. Share the key with a new joiner. Probably should be an option for admin, whether he wants to share (share the key) or does not want to share (generate new key and use it since that moment, old clients still remember old keys and can decrypt things).
    - madeofpalk 7y ago
      A single, shared key? Granted, I don't know much about encryption, end-to-end messaging, or otherwise, but it seems like a Very Hard Problem to solve for something like Slack.
      - vbezhenar 7y ago
        > A single, shared key? Yes, shared among participants. > it seems like a Very Hard Problem to solve for something like Slack. There are plenty of messengers with E2E encryption and group chats with working search. Sure, it's not a straightforward task and server-side handling of search and other functions makes everything much easier, but I don't think that it's impossible task. Though I'm not sure if demand is big enough. I would think that just self-hosting slack would be preferable for many organizations.
        madeofpalk 7y ago
        > Yes, shared among participants. Honest question - how does this work across thousands of employees, some of which are almost guaranteed to be bad-actors at one point? Or is that just not a problem that's trying to be solved? What are the impacts if someone leaks that? > There are plenty of messengers with E2E encryption and group chats with working search. I don't know - are they on the (user) scale of Slack? How many people can you add to a group in WhatsApp or iMessage? (I honestly don't know, but I would suspect Slack lets you have more people in a 'group' than them). Again, I have only a very cursory knowledge of how iMessage does E2E encryption. Obviously Slack would need to choose a different approach, but I wouldn't look at other messaging apps for examples.
  - johannes1234321 7y ago
    Yes, that could be done with e2e encryption. Typically a setup would use one secret key for crypting one (set of) message(s) and that key would be encrypted in a way that all authorized users can decrypt it. A new user then only needs access to the group key, which can be done cheaply (by anybody with access to the group key and all user's public keys)
  - ben_w 7y ago
    Unless the channels you’re on amount to at least one Bible-length document per day and you’re trying to index multiple years of content, the storage requirements for an index aren’t going to be a problem.
  - deadbunny 7y ago
    Not easily.
- thinkmassive 7y ago
  This seems to be how Matrix/Riot plan to enable search in E2E rooms: - https://github.com/matrix-org/matrix-search - https://github.com/vector-im/riot-web/issues/2548
- beatgammit 7y ago
  So, is each web client going to download the full history so it can build an index? I like being able to login from anywhere, but building a local index could take some time, and I definitely don't want that to happen when I first open slack in the browser.
  - quotemstr 7y ago
    That's what local storage is for.

ltbarcly3 7y ago

They could, but I don't think it would really add much benefit. One of the main features of Slack vs IRC is that Slack has persistent and consistent chat history. If you look at apps like Signal, when you log on from a new device your history isn't available, because of the end to end encryption used to store the messages. To view the history you would have to be able to decrypt it, but that means there has to be some mechanism for users joining a channel for the first time to decrypt the history of that channel (unless you want to break that functionality). Unless there is some really neat cryptography trick I'm not aware of, that would mean you can't have end to end encryption where each user's data is encrypted in a way that is opaque to everyone except user(s) in the chat like Signal or Telegram. Now I guess you could set up some kind of broker system and have like a different encryption key per channel or per conversation or something, which would at least mean some hacker has to get both the archived chats as well as the keys. This would make stealing chat histories more complicated, but not less possible.

yoz-y 7y ago
In iMessage this was possible but all combinations of pairs of your devices had their own keys. When a new device was added you needed to allow it from a device already registered and they would then sync messages device-to-device. This has resulted in quite a lot of mangled histories. Now with iMessage in iCloud, I do not know how the E2E encryption is done.
- konspence 7y ago
  >Now with iMessage in iCloud, I do not know how the E2E encryption is done It isn't done. Apple holds the master keys. The trust is that the iCloud server is not compromised.
  - yoz-y 7y ago
    I've read some discussions and key base articles and it seems that at least the master key is encrypted using your pin code. Not much, but I guess one could use a complex password.

leppr 7y ago

A read over Keybase's blog [1] makes one realize how non-trivial building a secure team chat is. We're still at a point in time where 99% of communities are ready to make exactly 0 compromise for privacy over usability. Slack is catering to the 99%. [1]: https://keybase.io/blog https://keybase.io/blog

fencepost 7y ago

Define "end." If one definition includes "the server(s)" then I'm positive it does at least on their Enterprise product, which notably last time I looked was the only one that could be considered HIPAA-compliant, aka "no your two - site medical practice can't use Slack to chat between the sites and coordinate anything involving patients."