• Dreeg Ocedam@lemmy.ml
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    3 years ago

    And this is not a theoretical threat either, something like that was done to identify democratic activists during the recent Hong-Kong protests and put them in jail.

    Source?

      • Palaress@lemmy.161.social
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        3 years ago

        Note that while this is about Telegram, this problem of reverse phone-number lookup also exists AFAIK with Signal.

        Where is the source for Signal? Because ASAIK there is no metadata accessible for Signal besides creation data of the account and the last time the account was online. No groups, no contacts, no anything. Source

        • poVoq@lemmy.ml
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          3 years ago

          You are missing the point. If you have a big list of suspect phone-numbers you can put them into Signal and it will show all that have their phone numbers registered with Signal. That is a metadata leak and quite a significant one.

          • Palaress@lemmy.161.social
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            3 years ago

            You are missing the point. If you have a big list of suspect phone-numbers you can put them into Signal and it will show all that have their phone numbers registered with Signal.

            Yes. That’s exactly what you get. A list of Signal users.

            That is a metadata leak and quite a significant one.

            Why is a user list in itself “a significant metadata leak”. You would need other information for that, like groups, contacts, online times or anything else. But you don’t get that, so I can only repeat my question: what is the problem with it?

            • poVoq@lemmy.ml
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              3 years ago

              I explained that already in much detail elsewhere in this thread.

              tl;dr as a Signal user you are a minority that is automatically suspect to law-enforcement and when this meta-data is overlapped with other meta-data is is easy to narrow down a list of suspects and get legal permission to deploy more intrusive surveillance methods. In addition once that more intrusive surveillance method is deployed on a device, it can read other linked phone-numbers from Signal group-chats and thus those people are also compromised because phone-numbers are always linked to government issued identities (either explicitly or due to payments).

          • Ferk@lemmy.ml
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            3 years ago

            You wouldn’t be able to know which of the Signal accounts actually belong to a particular group, or any other info other than them having an account. The example from the Hong-Kong protests is misdirected.

            With a big enough democrafic of the population using Signal, you wouldn’t even be able benefit much from knowing a number is in Signal… if every phone had a Signal account that metadata would be virtually useless.

            Sure, it’s a leak, but it’s one leak that also exists in Whatsapp and Telegram, along with many others leaks that those other messengers have and Signal doesn’t.

            I don’t use Signal, but I would definitely much rather recomend people use it rather than having billions of them continue with Whatsapp or Telegram. The whole point being made is that there’s a big difference between using Signal and using those, this is not about saying any particular form of communication is perfect. None are.

            • poVoq@lemmy.ml
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              3 years ago

              Sure, but other messengers that do not use phone-numbers do not leak this info. And as long as Signal is used by a certain minority it is a risky metadata leak.

              And you can turn this in any way you want, but using phone-numbers as the public identifier is a really bad idea and disqualifies Signal for most privacy sensitive communication. Even if everyone was using Signal it would be still a bad idea to hand out your phone number and have it visible in group-chats.

              • Ferk@lemmy.ml
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                3 years ago

                And yet Telegram and Whatsapp do that and more.

                We are not comparing Signal with “messengers that do not use phone-numbers” (which often leak other info instead). We are comparing it to messengers in the level of Telegram and Whatsapp, because the point was that placing it all on the same level isn’t accurate or fair. Reality isn’t Black&White.

                Signal has flaws, but I’d much rather have people asking me to communicate via Signal than through Telegram/Whatsapp as they usually do. I do wish Signal was able to catter to that demografic.

                • poVoq@lemmy.ml
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                  3 years ago

                  Why? That is like saying lets only compare really bad options with slightly less bad options.

                  Threema for example does not require phone numbers and there are also good XMPP based messengers.

                  • Ferk@lemmy.ml
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                    3 years ago

                    Because “slightly less” is a subjective measure that’s relative to how pedantic we want to get.

                    Even XMPP is a “slightly less” bad option, in the sense that you are still targetable when using a sufficiently advanced method, and you are still not free of risk. Even hosting your own instance you give away the IP, if you don’t hsot it then you do have to trust the host, since it does store metadata (maybe more so than Signal).