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This tradeoff is arguably a good thing. By using phone numbers as IDs signal can rely on your phone's local contacts (meaning they don't have to send your soci

This tradeoff is arguably a good thing. By using phone numbers as IDs signal can rely on your phone's local contacts (meaning they don't have to send your social graph to their servers). This way they can keep very little metadata on you. There's pretty much nothing for them to turn over except the fact that your phone number has the signal app. Most of the other secure apps could turn over your entire contact list (which could be damaging for people in a protest that are being targeted). Confirming a single phone number has the app is not nearly as big of a deal (I'd argue it doesn't matter at all).

Legogris 6y ago
I've lost track of the number of times I've had this conversation but here we go: There's nothing inherent in phone numbers here. Both iOS and Android also allows you to add e-mail addresses (and other identifiers) to your local contacts. I'm yet to hear an argument as to why e-mail addresses or other identifiers can't be used in addition to phone numbers, or why it would be a complicating factor.
- fossuser 6y ago
  My guess would be that phone numbers are guaranteed to be unique IDs that (almost) every phone will have which simplifies things and reduces the risk of someone impersonating someone else. I think they are working on non-phone number IDs though (Moxie was in an earlier signal thread on HN recently and mentioned it).
  - mikekchar 6y ago
    There is an issue on Github that is collating the problems they are working through. I've lost track of it, though, unfortunately. I've been pretty cynical about it in the past, but the last time I looked at the issue, it does look more complex than I first imagined. I wish it were higher priority, though. Hopefully somebody will remember the issue and post it here (it was from an HN post that I found it originally). Unfortunately, I'm not even sure what project it's under and there are many projects.
  - HenryBemis 6y ago
    In that spirit, emails (when discovered on a device) are also unique IDs. Even if someone's email is The-Dog@someprovider_dot_com authorities can still track that this mailbox was accessed by IP x.x.x.x and this IP is provided to phone number 555-12345 which belongs to Henry Bemis. It will take the authorities a bit more time (i.e. someone throws away their burner phone and authorities hack it)(with the assumption that phone numbers/SIM activations are provided using valid ID as it happens in many countries).
    - fsflover 6y ago
      You can access email only through Tor and they will never know your real IP.
      - nix23 6y ago
        Wrong...they probably don't know your IP..but a agency that has global surveillance in place, can find your source IP quite easy.
        fsflover 6y ago
        All typical attacks on Tor are known for many years already. If you follow the advises from the Tor website, it will be very hard (nearly impossible) to find you. What do you mean by "quite easy"?
        nix23 6y ago
        By quite easy i mean, when you have global surveillance in place. All tor-nodes are public all tor-exits are public, if your system can track connections from one node to another node and then the exit-node everything is clear. https://en.wikipedia.org/wiki/Global_surveillance#Infiltration_of_anonymous_networks https://en.wikipedia.org/wiki/Global_surveillance#Infiltrati... Edit: And that from netzpolitik (highly trusted german source) under 'A global passive adversary' that's the interesting part: https://netzpolitik.org/2017/secret-documents-reveal-german-foreign-spy-agency-bnd-attacks-the-anonymity-network-tor-and-advises-not-to-use-it/ https://netzpolitik.org/2017/secret-documents-reveal-german-...
  - ohhnoodont 6y ago
    Phone numbers are also guaranteed to be recycled. Every single whatsapp contact I have that's older than 3 years is no longer the original user. I know this because their profile picture is shown to me for some reason. Phone numbers are an outdated system that have no place in modern communication, especially not privacy software.
sneak 6y ago
iCloud contacts, which is how Apple phones store and sync this metadata for you, is not end to end encrypted, and is available to Apple and the military intelligence community without a warrant. https://sneak.berlin/20200604/if-zoom-is-wrong-so-is-apple/ https://sneak.berlin/20200604/if-zoom-is-wrong-so-is-apple/
soziawa 6y ago
> Most of the other secure apps could turn over your entire contact list (which could be damaging for people in a protest that are being targeted). But that doesn't help much if the entire contact list is a list of trash mail adresses (in the case of Wire) or a list of random IDs (in the case of Threema). And at least Threema does not store any information about your contacts on their servers. Can you obtain a phone number without any ID in the US? Because you can't in large parts of Europe.
- ardy42 6y ago
  > Can you obtain a phone number without any ID in the US? Because you can't in large parts of Europe. Yes. About 10 years ago, before Google Voice, I needed a local area-code number to work with my apartment buzzer. I bought a $15 Tracphone with cash at Walmart and activated it at a payphone (mainly just to see if I could).
- fossuser 6y ago
  Is it a list of trash mail addresses by default or is there an assumption that people made trash mail addresses specifically for the app? If it’s the latter, I suspect that won’t happen in practice for the majority of users. I haven’t heard of threema, I guess users have to share their IDs manually with each other in that case?
usertiljune2020 6y ago
The only keep my phone number, which is tied to my ID

Legogris 6y ago

I've lost track of the number of times I've had this conversation but here we go: There's nothing inherent in phone numbers here. Both iOS and Android also allows you to add e-mail addresses (and other identifiers) to your local contacts. I'm yet to hear an argument as to why e-mail addresses or other identifiers can't be used in addition to phone numbers, or why it would be a complicating factor.

fossuser 6y ago
My guess would be that phone numbers are guaranteed to be unique IDs that (almost) every phone will have which simplifies things and reduces the risk of someone impersonating someone else. I think they are working on non-phone number IDs though (Moxie was in an earlier signal thread on HN recently and mentioned it).
- mikekchar 6y ago
  There is an issue on Github that is collating the problems they are working through. I've lost track of it, though, unfortunately. I've been pretty cynical about it in the past, but the last time I looked at the issue, it does look more complex than I first imagined. I wish it were higher priority, though. Hopefully somebody will remember the issue and post it here (it was from an HN post that I found it originally). Unfortunately, I'm not even sure what project it's under and there are many projects.
- HenryBemis 6y ago
  In that spirit, emails (when discovered on a device) are also unique IDs. Even if someone's email is The-Dog@someprovider_dot_com authorities can still track that this mailbox was accessed by IP x.x.x.x and this IP is provided to phone number 555-12345 which belongs to Henry Bemis. It will take the authorities a bit more time (i.e. someone throws away their burner phone and authorities hack it)(with the assumption that phone numbers/SIM activations are provided using valid ID as it happens in many countries).
  - fsflover 6y ago
    You can access email only through Tor and they will never know your real IP.
    - nix23 6y ago
      Wrong...they probably don't know your IP..but a agency that has global surveillance in place, can find your source IP quite easy.
      - fsflover 6y ago
        All typical attacks on Tor are known for many years already. If you follow the advises from the Tor website, it will be very hard (nearly impossible) to find you. What do you mean by "quite easy"?
        nix23 6y ago
        By quite easy i mean, when you have global surveillance in place. All tor-nodes are public all tor-exits are public, if your system can track connections from one node to another node and then the exit-node everything is clear. https://en.wikipedia.org/wiki/Global_surveillance#Infiltration_of_anonymous_networks https://en.wikipedia.org/wiki/Global_surveillance#Infiltrati... Edit: And that from netzpolitik (highly trusted german source) under 'A global passive adversary' that's the interesting part: https://netzpolitik.org/2017/secret-documents-reveal-german-foreign-spy-agency-bnd-attacks-the-anonymity-network-tor-and-advises-not-to-use-it/ https://netzpolitik.org/2017/secret-documents-reveal-german-...
- ohhnoodont 6y ago
  Phone numbers are also guaranteed to be recycled. Every single whatsapp contact I have that's older than 3 years is no longer the original user. I know this because their profile picture is shown to me for some reason. Phone numbers are an outdated system that have no place in modern communication, especially not privacy software.

sneak 6y ago

iCloud contacts, which is how Apple phones store and sync this metadata for you, is not end to end encrypted, and is available to Apple and the military intelligence community without a warrant. https://sneak.berlin/20200604/if-zoom-is-wrong-so-is-apple/ https://sneak.berlin/20200604/if-zoom-is-wrong-so-is-apple/

soziawa 6y ago

> Most of the other secure apps could turn over your entire contact list (which could be damaging for people in a protest that are being targeted). But that doesn't help much if the entire contact list is a list of trash mail adresses (in the case of Wire) or a list of random IDs (in the case of Threema). And at least Threema does not store any information about your contacts on their servers. Can you obtain a phone number without any ID in the US? Because you can't in large parts of Europe.

ardy42 6y ago
> Can you obtain a phone number without any ID in the US? Because you can't in large parts of Europe. Yes. About 10 years ago, before Google Voice, I needed a local area-code number to work with my apartment buzzer. I bought a $15 Tracphone with cash at Walmart and activated it at a payphone (mainly just to see if I could).
fossuser 6y ago
Is it a list of trash mail addresses by default or is there an assumption that people made trash mail addresses specifically for the app? If it’s the latter, I suspect that won’t happen in practice for the majority of users. I haven’t heard of threema, I guess users have to share their IDs manually with each other in that case?

usertiljune2020 6y ago

The only keep my phone number, which is tied to my ID