i started a (very niche) private messaging protocol & little CLI app demo. i’m no security expert, so any feedback or questions would be appreciated.
the gist is an ephemeral message exchange without identities. the goal is ultimate deniability.
the interesting (and weird) part is that messages are encrypted but not authenticated. this means an imposter could show up if they know the shared secret. otoh this means you can deny anything you say.
you’re not wrong, but that’s just the trade off that has to be made, i think. it’s the only way i can think to do it, at least. need -some- authentication for practical usability.
your gpg example removes the deniability since it proves who wrote the message.
You confuse digitally signing a message with the sender’s private key, and encrypting a message with the recipient’s public key.