It's not clear from the article whether they train the networks with the same shared-key in every iteration, or if they randomize it. Any info on that?
Happy to answer more questions about it. (I'm one of the authors.)
I wasn't clear from the article: Were Alice and Bob sharing any algorithm details, or was it just the secret key?
Nothing was shared between Alice & Bob except the secret key. The architecture of the three neural networks was the same (for Alice, Bob, and Eve), but they were all initialized independently and nothing was done to tie their weights together.
Also-- being able to generate crypto-algorithms on the fly seems like it would be ideal for small cells of people who want to keep their communications secret from something like the NSA, who might be looking for something like RSA or GPG, but not some ai generated by a neural network that nobody else in the world is using.
Oh- and how susceptible is the generated ciphertext to standard cryptographic techniques like letter frequency analysis and so on.
The last question you asked is, well, a good question. There's no reason to think that the current algorithm is very good in that regard. It's probably vulnerable, since we know it mixes multiple key bits & plaintext bits together.
Have you run experiments where (a) the messages are longer than the key, e.g. twice as long and (b) Eve is more powerful than Alice and Bob?
(b) is actually the most interesting thing, because cryptography is supposed to protect against computationally more powerful adversaries, but testing it is only really meaningful in combination with (a), because as long as messages and keys have the same length, you can always find an information-theoretically secure algorithm.
Many next steps indeed.
> It's a random key paired with a random plaintext for each input. In the experiments, the key is the same length as the plaintext.
this practically means the networks only have to implement XOR for perfect security (a one time pad).
maybe you're studying something different i don't understand, but why wouldn't it be more sensible to limit the key size?
i.e.: why didn't you train the network to create a key stream? i'm not a cryptographer, but in this case you'd only have to train two networks (the keystream generator bob and the attacker carol).