The Signal protocol already guarantees repudiation: https://en.wikipedia.org/wiki/Signal_Protocol#Properties https://en.wikipedia.org/wiki/Signal_Protocol#Prope

The Signal protocol already guarantees repudiation: https://en.wikipedia.org/wiki/Signal_Protocol#Properties https://en.wikipedia.org/wiki/Signal_Protocol#Properties But this is just cryptographic repudiation, meaning that a receiver cannot prove that they didn't tamper with their Signal data to fake having received a message from a certain sender. OP is talking about something else: preventing any data the receiver might have received to be transferred to a 3rd-party, but that's impossible.