How do you solve that?
You encrypt the message for every device owned by every member of the group and then generate new keys on all of them and redo the key exchange for PFS.
Of course, you have to accept that once you reach a certain degree of publicity group chats are not secure at all and anonymity is *far* more important. This is why no one cares that IRC is completely in the clear but freak out about registering nick names.
By not having any friends to use it with.
Sadly, Whatsapp.
>>5
If you're going to use your phone number for ID and use a closed auto updating client you might as well just use MMS.
You contribute and implement this correctly but it's really hard and most of the time it's expensive.
https://datatracker.ietf.org/wg/mls/about/
https://en.wikipedia.org/wiki/Diffie-Hellman_key_exchange#Operation_with_more_than_two_parties
This seems like the right thing to me. You just have to make sure that the folks you're talking to are capable of maintaining the integrity of their private keys. If there is an actual threat one would imagine that you wouldn't want to speak to people incapable of this anyway.
>>8
The whole idea of secrets among groups is a bit silly if you ask me.
>>9
That's also a reasonable opinion. Even when administering a large secret organization, generally you would want to distribute secret information hierarchically and on a need to know basis. That being said perhaps to avoid targeted or automated manipulation it could be useful to encrypt conversations with your family and friends. It may then be that my last sentence in >>8 is false. Or perhaps it would be better to control information input (assumed primary means of manipulation) than to attempt to restrict reading of output. I don't know.
>>10
Right, but if you want to avoid automated targeting/manipulation you can't use phones at all. At that point you might as well use GPG.
>>11
Aye, all cell-phones have wiretaps, and I'm aware of blatant targeted advertising by Amazon using auditory data from similar devices. Still, it may be possible to reduce manipulation by limiting inputs for those which are incapable of removing their wiretap, or whose family and friends will not write to them using XMPP+PGP or what have you. I'm not sure if OP is looking for something practical for their situation or what their situation exactly is.
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