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It can even be bad for security: e2e encrypted messages are still replicated and stored on the servers. 30 years from now they might be decrypted by faster CPUs

It can even be bad for security: e2e encrypted messages are still replicated and stored on the servers. 30 years from now they might be decrypted by faster CPUs. Encrypted 1:1 messages should not be stored on servers! They should be sent between clients p2p stile or at least forwarded by servers without storing them.

Arathorn 8y ago
the reasons you need encrypted messages stored on the server are: * to synchronise them between multiple devices * if you lose your device, to have a hope of recovering your history * to be able to search them (either homomorphically or via a search bot you run) however, we're adding message retention configuration currently to let you limit how long your messages get persisted for (whether they're encrypted or not): https://github.com/matrix-org/matrix-doc/blob/matthew/msc1763/proposals/1763-configurable-retention-periods.md https://github.com/matrix-org/matrix-doc/blob/matthew/msc176...
cyphar 8y ago
If you recall that the NSA is already storing large amounts of internet traffic for later decryption, whether or not some server stores it is mostly irrelevant. Maybe you're worried about other lower-tech attackers, but I don't think that Matrix servers are going to keep 30 years of chat history (I imagine most Matrix servers are going to eventually use default retention policies). Not to mention you can run your own homeserver if you don't trust the operators of public homeservers. Storing 1:1 messages (noting that Matrix doesn't differentiate between group chats and 1:1 chats) on a server is beneficial because you might not want to lose your entire private chat history with your family and friends whenever you lose a device (source: this happened to me multiple times with Signal -- which has an awful backup system that I didn't use because it simply doesn't work properly). Now, there is obviously cases where you don't want the server to keep your messages forever -- and then you might want to have retention policies and so on. But I don't really agree with the security argument, since the most obvious attackers already likely have your messages, and it sacrifices a lot of convenience that most people expect (my partner didn't expect to lose all her Signal messages when her phone died unexpectedly).

Arathorn 8y ago

the reasons you need encrypted messages stored on the server are: * to synchronise them between multiple devices * if you lose your device, to have a hope of recovering your history * to be able to search them (either homomorphically or via a search bot you run) however, we're adding message retention configuration currently to let you limit how long your messages get persisted for (whether they're encrypted or not): https://github.com/matrix-org/matrix-doc/blob/matthew/msc1763/proposals/1763-configurable-retention-periods.md https://github.com/matrix-org/matrix-doc/blob/matthew/msc176...

cyphar 8y ago

If you recall that the NSA is already storing large amounts of internet traffic for later decryption, whether or not some server stores it is mostly irrelevant. Maybe you're worried about other lower-tech attackers, but I don't think that Matrix servers are going to keep 30 years of chat history (I imagine most Matrix servers are going to eventually use default retention policies). Not to mention you can run your own homeserver if you don't trust the operators of public homeservers. Storing 1:1 messages (noting that Matrix doesn't differentiate between group chats and 1:1 chats) on a server is beneficial because you might not want to lose your entire private chat history with your family and friends whenever you lose a device (source: this happened to me multiple times with Signal -- which has an awful backup system that I didn't use because it simply doesn't work properly). Now, there is obviously cases where you don't want the server to keep your messages forever -- and then you might want to have retention policies and so on. But I don't really agree with the security argument, since the most obvious attackers already likely have your messages, and it sacrifices a lot of convenience that most people expect (my partner didn't expect to lose all her Signal messages when her phone died unexpectedly).