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Ask HN: Secret messages in public forums

9 points by _mtkq ↗ HN
You might be familiar with movies/series where hidden/secret messages in public online forums/channels are part of the plot (involving some form of steganography).

Have you ever encountered such a situation (e.g., Reddit, or even HN)?

N.B. The staggeringly elaborate Cicada 3301 puzzle [1][2] does require deciphering steganographic messages, but they aren't posted in public channels.

[1] https://www.youtube.com/watch?v=RatbYqc0-jE

[2] https://uncovering-cicada.fandom.com/wiki/Uncovering_Cicada_Wiki

17 comments

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slater
7fa3b767c460b54a2be4d49030b349c7
Ghjklov
This is only vaguely related, but when I was younger I used to imagine a way for two people to communicate in secret openly without too much effort. Basically, person A will write messages to forum 1 under a decided alias and person B will respond to those messages on forum 2 under their decided alias. Two different forums, completely unrelated to each other, but only the two people will know where to look for the corresponding answer. To anyone else, it may look like total nonsense but if they hide it within posts that are vaguely on-topic, it could fly by with no one noticing at all.

Edit: Improved wording

mpiedrav
That's quite clever. In crypto literature, I guess it could be called like "covert cross-channel".

It turns out that the idea itself of communicating secrets in plain sight is called "subliminal channel" [1], which differs from steganography (hiding a message inside another message).

My question is not meant to imply conspiranoia. It's whether we as an audience of online forums have been fooled by this technique at some point.

[1] https://www.emsec.ruhr-uni-bochum.de/media/crypto/attachment...

gesman
Actually i had a better version of this:

Person A: says "hello Joe" Person B: answers: "Great to see you again buddy!"

After posting message, sender hashes his message with secret salt: "hello Joe" -> 2959D03A72B897C and then posts secret, real text to https://secret-share/#2959D03A72B897C

Receiver does the same to read the actual message.

Fun part?

Sender and receiver can actually piggyback on other people's conversations, twitter feeds, newpaper headlines this way to hide secret messages.

Ghjklov
I like that a lot. And we are just two random people with random ideas. Just imagine the variety of ways people are already secretly communicating right now right in the open and none of us are any wiser.
gesman
Absolutely.

The best way to hide the secret is to make adversary believe that secret does not exist

rococode
There was a mysterious sub on Reddit that had random encrypted messages being posted. I believe the original sub is private now but the sub that discussed it is still up, /r/Solving_A858.

https://old.reddit.com/r/Solving_A858/

thecupisblue
Saw it once, I think it might be someone's storage. Use reddit to save hashed data. Or DNS!
dnh44
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jnichols35
I saw this a few years ago on Reddit and wish I had saved the thread because it was pretty interesting.

I was reading a thread between two users that seemed totally normal until a user posted a screenshot of their comments. It showed a second conversation between them that was happening in secret. If memory serves the person who posted the screenshot said it was an extension (possibly RES) where you view certain tags and allows you to see the extra comments based on the tags.

After seeing that I couldn't help but wonder how many secret conversations were happening out in the open on Reddit.

[deleted]
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rshnotsecure
Yes this happens all the time and how is modern espionage, for the time being, extensively communicates.

Typically this happens on websites that look like junk/ad websites to you and me. Also sometimes they will look like the ads you see on parked domains.

There will be hidden words, or perhaps you will need to know how to adjust the CSS in chrome developer tools. Often times it is a small URI fragment you need to append to the URL, or a specific place to click every time.

Again I want to emphasize how common this is, and the “dark web” is not used nearly as much in terms of overall volume by such groups.

Owlhousing.com was until recently and still probably is one such site. It looked like some junk casino ad website, but scroll down for a very lengthy period and you would find...sophisticated electronic Microscopes for sale out of Hong Kong. Now it is some car website.

The best way to find these websites is to use Spyse.com. Using the “prefix” search operator enter something like “000000000” or “aaaaaaaaa”. Hundreds if not thousands of sites show up. No real person would take out these domains. Start with them.

beckingz
Instagram as command and control infrastructure for malware.