4 ms·

Because of public-key crypto, it doesn't matter if the servers are malicious.

by jolmg 6y ago

kitkat_new 6y ago
not true with respect to meta data
- jolmg 6y ago
  which I don't think is as concerning, but is there a particular piece of metadata that concerns you?
  - codethief 6y ago
    I do think it is a valid concern. Over the years, various sources reported that intelligence agencies mostly use metadata (who's talking to whom, i.e. the social network) in their analysis because message content is harder to parse and understand (and, outside of email traffic, harder to obtain in the first place).
  - fuzzylightbulb 6y ago
    https://www.sciencemag.org/news/2016/05/your-call-and-text-records-are-far-more-revealing-you-think https://www.sciencemag.org/news/2016/05/your-call-and-text-r... Metadata can be as damning as the actual message data, and in a lot of places you don't want the authorities to know that you are even communicating at all.
  - acct776 6y ago
    Certain parts of the world, people get bombed on metadata alone.
cassianoleal 6y ago
Assuming you have: - read the source code and are satisfied that it's secure - compiled that version of the code - installed it on your mobile or desktop You're still only as secure as the client on the other side of the conversation. If that one is compromised (has not gone throught the steps above) it could very well be sending all messages in clear text to a malicious party. Edit: formatting
- jolmg 6y ago
  Ok, sure. But what do you propose? It's still a much better situation than what we have with Whatsapp. Is there something that the Signal Foundation could do to alleviate that concern you have? There's no technical solution in any technology for preventing the other side being compromised, as far as I can see.
  - cassianoleal 6y ago
    At present I'm choosing to trust Signal. That doesn't mean I blindly trust them, only that despite seeing potential for abuse I judge that they have more incentive to be telling the truth than not. Also check the comment by user faitswulff where they mention how they have been subpoenaed "and could only supply account creation time and last connection time".
  - HengYeDev 6y ago
    Matrix since you can self-host and have control while still being able to communicate to other people on it through federation
    - jolmg 6y ago
      >>> You're still only as secure as the client on the other side of the conversation. If that one is compromised ... it could very well be sending all messages in clear text to a malicious party. >> There's no technical solution in any technology for preventing the other side being compromised, as far as I can see. I don't know Matrix, but I can guarantee that it doesn't solve the problem of a compromised client obtaining the messages willingly sent to it.
- Enginerrrd 6y ago
  Yeah and since you have the possibility of dealing with state actors with deep pockets, you have to wonder if Android or iOS doesn't have the ability to copy your private keys and send those off somewhere for storage. Because of signal's popularity, it feels pretty possible to me. If the NSA did have it backdoored somehow through the OS, it's a good bet they'd force LE agencies to use parallel construction to keep that information top secret. That is why we really need open source hardware and OS's. A good (or even functional) open linux phone can't come fast enough.
sneak 6y ago
The server can MITM the public keys, providing you with a key from the server instead of the key from your conversation partner. It very much does matter if the server is malicious.
- henearkr 6y ago
  Not if the keys are generated by the client. Signal also offers to label contacts for which you could verify the authenticity by another way. Doing a video call with the contact can be a simple way to clear doubts, even if it is not a proper different channel.
  - sneak 6y ago
    This is false. A video call will not prevent or detect MITM. You may be suggesting that a video call is used to authenticate the key, which is certainly a step in the right direction, but I don't think Signal supports this.
    - henearkr 6y ago
      It will, because it will prove (or give you a lot of confidence) that the agent who sent you their public key is your legit correspondent. This uses the fact that the client on each side is open source and inspectable, so that each side knows that they sent only the public key that they generated on their own device. PS: to answer your last sentence, Signal allows you to flag specifically contacts that you managed to verify. Which is technically equivalent to say that you verified that the public key is theirs.
      - sneak 6y ago
        Yes, but it doesn't support doing that whilst in a video call with them.
        henearkr 6y ago
        [edited] Indeed it is far from straightforward that merely doing a video call suffices to check the keys. Signal is famously using a special protocol for secure key sharing through the server, which I have not studied. But as said by another comment, there is no way around verifying explicitly the public key using an independent channel.

Because of public-key crypto, it doesn't matter if the servers are malicious.

by jolmg 6y ago

Because of public-key crypto, it doesn't matter if the servers are malicious.

kitkat_new 6y ago

not true with respect to meta data

jolmg 6y ago
which I don't think is as concerning, but is there a particular piece of metadata that concerns you?
- codethief 6y ago
  I do think it is a valid concern. Over the years, various sources reported that intelligence agencies mostly use metadata (who's talking to whom, i.e. the social network) in their analysis because message content is harder to parse and understand (and, outside of email traffic, harder to obtain in the first place).
- fuzzylightbulb 6y ago
  https://www.sciencemag.org/news/2016/05/your-call-and-text-records-are-far-more-revealing-you-think https://www.sciencemag.org/news/2016/05/your-call-and-text-r... Metadata can be as damning as the actual message data, and in a lot of places you don't want the authorities to know that you are even communicating at all.
- acct776 6y ago
  Certain parts of the world, people get bombed on metadata alone.

cassianoleal 6y ago

Assuming you have: - read the source code and are satisfied that it's secure - compiled that version of the code - installed it on your mobile or desktop You're still only as secure as the client on the other side of the conversation. If that one is compromised (has not gone throught the steps above) it could very well be sending all messages in clear text to a malicious party. Edit: formatting

jolmg 6y ago
Ok, sure. But what do you propose? It's still a much better situation than what we have with Whatsapp. Is there something that the Signal Foundation could do to alleviate that concern you have? There's no technical solution in any technology for preventing the other side being compromised, as far as I can see.
- cassianoleal 6y ago
  At present I'm choosing to trust Signal. That doesn't mean I blindly trust them, only that despite seeing potential for abuse I judge that they have more incentive to be telling the truth than not. Also check the comment by user faitswulff where they mention how they have been subpoenaed "and could only supply account creation time and last connection time".
- HengYeDev 6y ago
  Matrix since you can self-host and have control while still being able to communicate to other people on it through federation
  - jolmg 6y ago
    >>> You're still only as secure as the client on the other side of the conversation. If that one is compromised ... it could very well be sending all messages in clear text to a malicious party. >> There's no technical solution in any technology for preventing the other side being compromised, as far as I can see. I don't know Matrix, but I can guarantee that it doesn't solve the problem of a compromised client obtaining the messages willingly sent to it.
Enginerrrd 6y ago
Yeah and since you have the possibility of dealing with state actors with deep pockets, you have to wonder if Android or iOS doesn't have the ability to copy your private keys and send those off somewhere for storage. Because of signal's popularity, it feels pretty possible to me. If the NSA did have it backdoored somehow through the OS, it's a good bet they'd force LE agencies to use parallel construction to keep that information top secret. That is why we really need open source hardware and OS's. A good (or even functional) open linux phone can't come fast enough.

sneak 6y ago

The server can MITM the public keys, providing you with a key from the server instead of the key from your conversation partner. It very much does matter if the server is malicious.

henearkr 6y ago
Not if the keys are generated by the client. Signal also offers to label contacts for which you could verify the authenticity by another way. Doing a video call with the contact can be a simple way to clear doubts, even if it is not a proper different channel.
- sneak 6y ago
  This is false. A video call will not prevent or detect MITM. You may be suggesting that a video call is used to authenticate the key, which is certainly a step in the right direction, but I don't think Signal supports this.
  - henearkr 6y ago
    It will, because it will prove (or give you a lot of confidence) that the agent who sent you their public key is your legit correspondent. This uses the fact that the client on each side is open source and inspectable, so that each side knows that they sent only the public key that they generated on their own device. PS: to answer your last sentence, Signal allows you to flag specifically contacts that you managed to verify. Which is technically equivalent to say that you verified that the public key is theirs.
    - sneak 6y ago
      Yes, but it doesn't support doing that whilst in a video call with them.
      - henearkr 6y ago
        [edited] Indeed it is far from straightforward that merely doing a video call suffices to check the keys. Signal is famously using a special protocol for secure key sharing through the server, which I have not studied. But as said by another comment, there is no way around verifying explicitly the public key using an independent channel.