Why don't they just use hashed pairs of telefone numbers for discovery? I'm more worried that they have my whole telefone contact list, than that they know with

Why don't they just use hashed pairs of telefone numbers for discovery? I'm more worried that they have my whole telefone contact list, than that they know with whom I am chatting. They could probably find out the latter by manipulating the client anyway. Also, don't they neccessarily have a mapping of telefone number -> IP address? They could just show all contacts, and attempt to send if you write to somebody. If they want to only show mutuals, use the hashed pairs to get the IP address (or ID, or status, or whatever they need). I don't want to be too negative, but this seems to me like an unnecessary complex solution to a problem I don't have. I'd rather have the option to register anonymously, or to use alternative clients and servers. Also, as a layperson, they could be making all of this up and I would never be able to tell. Somebody could have bought or coerced a couple of security experts that I know and trust, and I would never be able to find out. So, in a sense, a dumber and less secure solution might actually be better...