[Cryptography] New White Paper: GhostLine - Information-Theoretically Secure Multi-Party Chat

[Jerry Leichter]

Missing from all this discussion is quantum key distribution.  *In principle* this offers a way for participants to agree on truly random sequence of bits.  "Truly random" here is based on (a) assumptions about physics that are at least as well supported as any assumptions you could make to validate the performance of any physical source of randomness; (b) the actual engineering of such systems has proven to be quite tricky, though it *appears* the problems are now solved.

Note that, as with many things when you go from classical to quantum mechanics, some truths ... no longer are.  This mechanism gives a way to securely share a one-time pad - but the same mechanism provably *cannot* be used to transmit the actual data bits.

QKD has its own set of limitations and I'm not in any way recommending it.  Whether it has any real role to play (other than as a way to get funding for some neat physics - and some perhaps not-so-neat startups) is debatable.  But if we're going to discuss one-time pads, it should be part of the conversation.
                                                        -- Jerry