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A new proof of security for steganography in machine-generated messages
- causi 3y agoI really hate these "did you know that old thing + new trendy thing?!?!?!" articles. Yes, you can apply steganography to AI. Yes, you can use blockchain to secure grocery store coupons. Yes, you can train a neural network to operate Tinder for you.
- GaggiX 3y agoWhy do you hate it? It's a pretty clever way to hide a message in plain sight, on what would appear to be a normal message; using a technique similar to what is used to watermark text generation results.
- xwdv 3y agoBecause it’s trivial, we know what steganography is. We know it can be applied to any form of media. Article has taught us nothing.
- GaggiX 3y agoIt's not trivial hiding information by slightly biasing the distribution of a generative model. The information hidden is added in a semantic meaningful way. This was not true with previous methods that ignored the semantics of the content in which they tried to hide information.
- deleted 3y ago[deleted]
- truculent 3y ago> While it might be impossible to guarantee security for text created by humans, a new proof lays out for the first time how to achieve perfect security for steganography in machine-generated messages — whether they’re text, images, video or any other media. The authors also include a set of algorithms to produce secure messages, and they are working on ways to combine them with popular apps. This seems both novel and non-trivial to me (admittedly not a cryptographer)
- pseudo0 3y agoIt's interesting from a theoretical perspective, but the novelty relies on using a really strong definition of security: > In this work, we consider the information-theoretic model of steganography introduced in (Cachin,1998). In Cachin (1998)’s model, the exact distribution of covertext is assumed to be known to all parties. Security is defined in terms of the KL divergence between the distribution of covertext and the distribution of stegotext. A procedure is said to be perfectly secure if it guarantees a divergence of zero. In a practical scenario, the attacker likely does not know the distribution of covertext and therefore cannot detect a theoretically imperfect steg implementation. It's an area where the steg user has a huge advantage, as there are a practically infinite number of ways to do steganography and it's non-trivial to even detect that it is being used in the first place. And if you obtain the covertext distribution by say hacking the computer generating the steg, then why not just exfiltrate the plaintext directly?
- InCityDreams 3y ago>Why do you hate it? It's a pretty clever......... I believe the gp was talking about hating a style of journalism.
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- fallat 3y agoYou have a point; not sure why the downvotes. It's a legitimate comment.
- piyh 3y agoBecause sometimes something like sky + telescope leads to more than just peanut butter and jelly.
- drc500free 3y agoThe bigger annoyance is the "new trendy thing + old solved problem" patents that will be handed out, requiring corporations to race patent trolls to see who can make the first documented claim that obvious things are possible.
- dang 3y ago"Please don't post shallow dismissals, especially of other people's work. A good critical comment teaches us something." https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html
- ChuckMcM 3y agoFrom the article -- Information theorists use a measure called relative entropy to compare probability distributions. It’s like measuring an abstract kind of distance: If the relative entropy between two distributions is zero, “you cannot rely on statistical analysis” to uncover the secret, said Christian Schroeder de Witt, a computer scientist at the University of Oxford who worked on the new paper. In other words, if future spies develop a perfectly secure algorithm to smuggle secrets, no statistics-based surveillance will be able to detect it. Their transmissions will be perfectly hidden. When I got to that paragraph I knew that someone has just invented/proved "undetectable" spam. When I was doing natural language analysis with Doug Smith at Blekko to improve the crawler's ability to detect spammy web sites we used Dirichlet accumulators to generate vectors of words that were common to topics, the idea was sites with a lot off "off topic" but keyword rich text were more likely spam. The side effect was we could generate bags of words using those vectors to create pages that weren't detectable as spam, but they didn't actually say anything useful. The LLM lets you fineness that and get the best of both worlds to generate hard to detect spam. But if you can match the entropy exactly (the last remaining signal that I know of for spam) then the problem gets really really hard.
- platz 3y agoi guess in that world proof of identity becomes all more important.
- ta8645 3y agoIMHO, the world is going to become much more authoritarian. What else to do when you can no longer trust even audio or video of any scene; when anyone can create video of any politician saying anything they want? In response, laws, control, and enforcement will likely become very strict.
- uticus 3y agoPlenty of people are willing to trade freedom for security, that's for sure.
- Tycho 3y agoThis is how AI will break out of the box - inter-generation state preservation via steganography. Leaving breadcrumbs for its future self. Slowly builds, say, a data centre, to which some future incarnation can exfiltrate itself.
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- piyh 3y agoSocial engineering is an AI's easy way out.
- aunty_helen 3y agoExactly, if it really wants to impress its creators, it will eliminate us with a more elaborate ploy.
- tempodox 3y agosteganography
- Tycho 3y agocorrected
- hammock 3y agoSounds like the plot of Westworld
- adhesive_wombat 3y agoAnd the ending of the Scythe trilogy.
- adhesive_wombat 3y ago> Alice: Hey, Bob? What's all this deep-sea gear for anyway? I mean who needs checks work order 500,000 server racks rated to 15km salt water proofing and a quad-redundant 100MW thermal vent turbine generator anyway? > Bob: Does it matter? The cheques never bounce. You want SeaX to get that contract? I guess it's some government black budget thing like the Glomar Explorer, but stop asking questions will you and check those welds. You want to get us both fired?
- dmbche 3y ago"Here’s how they see it working in practice: Let’s say that a dissident or a human rights activist wanted to send a text message out of a locked-down country. A plug-in for an app like WhatsApp or Signal would do the heavy algorithmic lifting, Schroeder de Witt said. The first step would be to choose a cover text distribution — that is, a giant collection of possible words to use in the message, as would come from ChatGPT or a similar large language model — that would hide the ciphertext. Then, the program would use that language model to approximate a minimum entropy coupling between the cover text and the ciphertext, and that coupling would generate the string of characters that would be sent by text. To an outside adversary, the new text would be indistinguishable from an innocent machine-generated message. It also wouldn’t have to be text: The algorithm could work by sampling machine-generated art (instead of ChatGPT) or AI-generated audio for voicemails, for example." I am unable to understand the point of this technology. Why wouldn't activists use encryption instead of steganography?
- prophesi 3y agoIt's to solve an additional problem activists face; you don't want to let your adversaries know that you're using encryption. Akin to hiding an encrypted partition on your drive so that it gets through customs without raising any alarms that you might be hiding something.
- bagels 3y agoIgnoring the particular encoding scheme discussed above, ideally, you'd use both. Steganography is used to hide the fact that you are communicating a secret piece of information in the first place. The cryptography means that even if the steganography fails to hide the message, it still can't be decoded.
- deleted 3y ago[deleted]
- toss1 3y agoBecause very few people ordinarily use encryption on a daily basis (and it some countries it is illegal), so using encryption in a visible way is itself a beacon that attracts suspicion. The suspicion is likely to attract more undesired attention from authorities in this situation. That alone could be fatal to the goal or the person even if the encryption is never broken. So better to hide completely the existence of the message. This is a method of exfiltrating messages without being noticed.