1. 22
  1.  

  2. 12

    Does anyone else find it odd that the #1 private messaging app, promoted by Snowden, requires your phone number? Yes I know you can use a burner, but why?

    And they hash your contacts and upload them. You know, the weird thing about phone numbers is there’s a finite number of them and they are recorded in a database. Hashing every number wouldn’t take but a few days, or hours at state actor level.

    1. 6

      And they hash your contacts and upload them. You know, the weird thing about phone numbers is there’s a finite number of them and they are recorded in a database. Hashing every number wouldn’t take but a few days, or hours at state actor level.

      Rather than downvote you as “incorrect,” here’s their blog post on how private contact discovery for Signal works.

      1. 2

        Would it be correct to then say that they instead use an encrypted “truncated SHA256 hash of each phone number”?

        Also, does the following mean that the encrypted session is managed by the secure enclave with no access by the host OS? Just want to make sure I’m understanding it correctly. It seems secure if this is the case.

        “Clients that wish to perform contact discovery negotiate a secure connection over the network all the way through the remote OS to the enclave.”

        Thanks for pointing I’m wrong, to be honest I thought I would get hammered with downvotes for that comment, was kind of hoping someone would have more information on it.

        1. 2

          Would it be correct to then say that they instead use an encrypted “truncated SHA256 hash of each phone number”?

          The truncated SHA1 hash of the base64 of each phone number.

          Also, does the following mean that the encrypted session is managed by the secure enclave with no access by the host OS?

          Yes.

      2. 5

        Read Mathew’s, from Riot, post about signal and their ideas about privacy, you would find it interesting.

        1. 3

          Yup. But the app promises privacy, not complete anonymity.

          1. 3

            For me it is not odd, but an annoyance. It is not phone number based identity that enables private communication, but other features such as sealed sender.

            But you might want to read up about this recent posting of Signal Technology Preview for secure value recovery which is their research that will/might eventually enable non-phone-number based identities.

          2. 1

            It annoys me that they rejected this. A menu literally tucks away complexity for those who aren’t looking for it. I wonder if they would have accepted it from someone with a different handle. Anyway, thank you for submitting the PR, and for this blog post.