4 ms·

May I recommend Delta Chat? It's an email client (with clever, seamless encryption based on gpg) with a WhatsApp style interface. There's a desktop client too.

by hkt 6y ago

May I recommend Delta Chat? It's an email client (with clever, seamless encryption based on gpg) with a WhatsApp style interface. There's a desktop client too. I've only ever managed to get one person to use it, but goodness it'd be nice to get rid of WhatsApp. Edit: URL https://delta.chat/ https://delta.chat/

dan-robertson 6y ago
Note that gpg provides worse security from an encryption standpoint than signal/WhatsApp
- hkt 6y ago
  Care to explain?
  - mnw21cam 6y ago
    No perfect forward security. It's a feature, not a bug.
    - dan-robertson 6y ago
      It doesn’t feel like a feature to me. And neither does the lack of deniability. They both feel like things that leak information that doesn’t need to be leaked.
      - hkt 6y ago
        Seems somewhat like threat model will determine the need for deniability etc. I don't consider myself to need it, and mine seems like a common enough case - compatible with a normal WhatsApp user's use case.
      - mnw21cam 6y ago
        Perfect forward secrecy requires two-way real-time communication, in order to construct a session key that can't be computed from just the private keys and the encrypted message. Therefore the way that PGP's lack of perfect forward secrecy is a feature is that it allows an encrypted message to be generated in a way that doesn't require two-way real-time communication, and can therefore be sent by email. The trade-off is that you then don't have perfect forward secrecy.
        dan-robertson 6y ago
        Why does signal still work when the other party is offline?
  - h_anna_h 6y ago
    whatsapp and signal have forward secrecy, so if your private key is leaked it means that past conversations can't be decrypted. In reality it does not offer a lot of protection if you don't disable keeping logs (because losing your phone and malware are the only realistic ways of your private key being leaked). In addition the way that they have forward secrecy implemented it means that you have to decrypt every message posted in groupchats while you were offline sequently until the last one, which can take hours in an active (even if small) group if you are gone for a week. The other thing is that both of these apps to my knowledge do not warn you if a new key is added (I might be wrong here) so an active attacker can pretty much nullify the encryption, this is not an issue with openpgp.
    - dan-robertson 6y ago
      To add to this: the point of the disappearing messages in signal is to enhance the value of the forward secrecy by not having the record of the messages (so long as both devices are using correct clients and no one is screenshotting messages. The other feature is deniability: having an encrypted message and it’s decryption doesn’t give you any more information than a screenshot of the message in signal. There isn’t a way for the encrypted message to prove that it was legitimate as the previous keys are revealed in a way that means anyone sniffing the traffic could make a message encrypted with that key.
      - h_anna_h 6y ago
        Afaik, the messages should be deniable as long as they are not signed, not sure how delta chat handles it though. Regarding deniability I personally would consider it as an anti-feature because the one receiving the message can't prove to the wider world that they received it from a certain person and similarly someone who is falsely accused of posting a certain message can't go and say "show the signatures of the messages or you are lying". By the way, do you know if the one receiving the messages can force messages that are marked as "disappearing" to be kept?
        dan-robertson 6y ago
- lucb1e 6y ago
  Frankly, I don't even care if it uses end-to-end encryption at all if it's encrypted to my own server. Of course, email goes between servers and then you definitely want to ensure the encryption is solid (it often isn't, so PGP is definitely good). I'm just saying that Wire/Signal/Threema/etc. having better encryption is in my opinion only important when you use Wire's/Signal's/Threema's servers. If you can and do host your own, especially if you host it at home, then in practice there is no difference. Since most people don't do that, Signal/Wire/Threema/Matrix are of course the better options than PGP+email, but PGP+email is still an improvement over the status quo.

by hkt 6y ago

dan-robertson 6y ago

Note that gpg provides worse security from an encryption standpoint than signal/WhatsApp

hkt 6y ago
Care to explain?
- mnw21cam 6y ago
  No perfect forward security. It's a feature, not a bug.
  - dan-robertson 6y ago
    It doesn’t feel like a feature to me. And neither does the lack of deniability. They both feel like things that leak information that doesn’t need to be leaked.
    - hkt 6y ago
      Seems somewhat like threat model will determine the need for deniability etc. I don't consider myself to need it, and mine seems like a common enough case - compatible with a normal WhatsApp user's use case.
    - mnw21cam 6y ago
      Perfect forward secrecy requires two-way real-time communication, in order to construct a session key that can't be computed from just the private keys and the encrypted message. Therefore the way that PGP's lack of perfect forward secrecy is a feature is that it allows an encrypted message to be generated in a way that doesn't require two-way real-time communication, and can therefore be sent by email. The trade-off is that you then don't have perfect forward secrecy.
      - dan-robertson 6y ago
        Why does signal still work when the other party is offline?
- h_anna_h 6y ago
  whatsapp and signal have forward secrecy, so if your private key is leaked it means that past conversations can't be decrypted. In reality it does not offer a lot of protection if you don't disable keeping logs (because losing your phone and malware are the only realistic ways of your private key being leaked). In addition the way that they have forward secrecy implemented it means that you have to decrypt every message posted in groupchats while you were offline sequently until the last one, which can take hours in an active (even if small) group if you are gone for a week. The other thing is that both of these apps to my knowledge do not warn you if a new key is added (I might be wrong here) so an active attacker can pretty much nullify the encryption, this is not an issue with openpgp.
  - dan-robertson 6y ago
    To add to this: the point of the disappearing messages in signal is to enhance the value of the forward secrecy by not having the record of the messages (so long as both devices are using correct clients and no one is screenshotting messages. The other feature is deniability: having an encrypted message and it’s decryption doesn’t give you any more information than a screenshot of the message in signal. There isn’t a way for the encrypted message to prove that it was legitimate as the previous keys are revealed in a way that means anyone sniffing the traffic could make a message encrypted with that key.
    - h_anna_h 6y ago
      Afaik, the messages should be deniable as long as they are not signed, not sure how delta chat handles it though. Regarding deniability I personally would consider it as an anti-feature because the one receiving the message can't prove to the wider world that they received it from a certain person and similarly someone who is falsely accused of posting a certain message can't go and say "show the signatures of the messages or you are lying". By the way, do you know if the one receiving the messages can force messages that are marked as "disappearing" to be kept?
      - dan-robertson 6y ago
lucb1e 6y ago
Frankly, I don't even care if it uses end-to-end encryption at all if it's encrypted to my own server. Of course, email goes between servers and then you definitely want to ensure the encryption is solid (it often isn't, so PGP is definitely good). I'm just saying that Wire/Signal/Threema/etc. having better encryption is in my opinion only important when you use Wire's/Signal's/Threema's servers. If you can and do host your own, especially if you host it at home, then in practice there is no difference. Since most people don't do that, Signal/Wire/Threema/Matrix are of course the better options than PGP+email, but PGP+email is still an improvement over the status quo.