4 ms·

Why not share the contact list with the people on your contact list? Facebook demonstrated that most people don't have a problem with that and most people I wan

Why not share the contact list with the people on your contact list? Facebook demonstrated that most people don't have a problem with that and most people I want to contact are already contacts of some contacts that I have.

Arnt 11y ago
That's the goal. The problem is discovering it. If x has me on the list and I have x on the list, how can our two Signal apps discover that? Without telling the Signal server, and without telling random third parties?
- Tepix 11y ago
  There needs to be a decentralized way to tell [some of] your contacts directly that you have app X installed (or that you support messaging protocol Y).
  - Arnt 11y ago
    "Some of", you say. Tell all of the contacts is simple, just send them an SMS. But you probably don't want that, right? Maybe you even don't want everyone to know what apps you use? So it's "some of", at which point you're back to the same problem: Discovering which of the contacts to tell. Like so many networking problems, this one is easy to solve provided that it's already solved by someone else. See RFC 1925 points 6 and 6a.
    - Tepix 11y ago
      RFC 1925 has no points 6 and 6a. Did you mean 2.6 and 2.6a? What you could do is publish the information which apps you have or which protocols you support using FOAF spheres [http://reagle.org/joseph/2003/09/foaf-spheres.html http://reagle.org/joseph/2003/09/foaf-spheres.html]. Encrypt the information using the public keys of your friends. Publish the information on your private web server so no central entity can see who retrieves it.
- zeveb 11y ago
  > If x has me on the list and I have x on the list, how can our two Signal apps discover that? Without telling the Signal server, and without telling random third parties? Take a look at the protocol documented in https://news.ycombinator.com/item?id=11289223 https://news.ycombinator.com/item?id=11289223 It's secure against an honest server and a malicious person, and against a dishonest server; it's insecure against a colluding server and person.
  - Arnt 11y ago
    Fascinating algorithm. I wonder how many Signal users it would discover in the ~500 typical contacts, given one starting contact.
newman314 11y ago
I have United and other services in my addressbook. This is a non-starter as I don't want to have to selectively determine on a case-by-case basis who to or not to send to.

Arnt 11y ago

That's the goal. The problem is discovering it. If x has me on the list and I have x on the list, how can our two Signal apps discover that? Without telling the Signal server, and without telling random third parties?

Tepix 11y ago
There needs to be a decentralized way to tell [some of] your contacts directly that you have app X installed (or that you support messaging protocol Y).
- Arnt 11y ago
  "Some of", you say. Tell all of the contacts is simple, just send them an SMS. But you probably don't want that, right? Maybe you even don't want everyone to know what apps you use? So it's "some of", at which point you're back to the same problem: Discovering which of the contacts to tell. Like so many networking problems, this one is easy to solve provided that it's already solved by someone else. See RFC 1925 points 6 and 6a.
  - Tepix 11y ago
    RFC 1925 has no points 6 and 6a. Did you mean 2.6 and 2.6a? What you could do is publish the information which apps you have or which protocols you support using FOAF spheres [http://reagle.org/joseph/2003/09/foaf-spheres.html http://reagle.org/joseph/2003/09/foaf-spheres.html]. Encrypt the information using the public keys of your friends. Publish the information on your private web server so no central entity can see who retrieves it.
zeveb 11y ago
> If x has me on the list and I have x on the list, how can our two Signal apps discover that? Without telling the Signal server, and without telling random third parties? Take a look at the protocol documented in https://news.ycombinator.com/item?id=11289223 https://news.ycombinator.com/item?id=11289223 It's secure against an honest server and a malicious person, and against a dishonest server; it's insecure against a colluding server and person.
- Arnt 11y ago
  Fascinating algorithm. I wonder how many Signal users it would discover in the ~500 typical contacts, given one starting contact.

newman314 11y ago

I have United and other services in my addressbook. This is a non-starter as I don't want to have to selectively determine on a case-by-case basis who to or not to send to.