| Looks like a few folks are confused. 1. One of the underlying cryptographic principles is multi-party / secure-party communication (https://en.wikipedia.org/wiki/Secure_multi-party_computation). e.g., three people want to share their salaries to each other, but don't want the information to be traceable to back to the source. 2. Another is Steganography, hiding text in, say, an image, or audio. 3. You want to prevent the problems with Signal, Tor, Bitcoin, etc. This means, no "50%" problem like Bitcoin, no monitoring of exit nodes like Tor, no centralized distribution issue like Signal. Imagine: Alice "sends" a message to Bob by creating an account on Reddit and posts a cat meme which has the hidden text (steganography). Bob knows how to find the text in that cat meme, and responds by posting something on Twitter, which Alice can read and decrypt. All this is deniable (I didn't get anything from Alice!), available (e.g., Twitter goes down), and secure. |
The approach has limitations: your bandwidth is very low, and your latency is also pretty poor. Worse yet, you have to first establish a complicated protocol between you and your counterparty. In general, I think, it's not cracking your byzantine protocol that would ruin you, but a couple of small opsec mistakes (see Dread Pirate Roberts and the end of Silk Road), and these mistakes may be not even done by you but by your counterparty. Spear-phising, exploiting the local system that runs the communication and has some sensitive material in plain text, game over.
The problem with highly secure and clandestine communication (or any other activity) is that it makes your whole life complicated enough, puts enough extra strain on you, that you become noticeable by that alone. Maybe not immediately, but the probability of a small mistake that could put you on a watch-just-in-case list of a willing state-level actor is always nonzero. This does not mean that the situation is hopeless, but rather means that you have a time limit before your cat-posting scheme, still unbroken, becomes irrelevant, given enough interest from The Man against whom you conspire.