Literally what Minimodem was created for :)
Minimodem – general-purpose software audio FSK modem
152 points | by marcodiego | 55 days ago | 38 comments
- "oh, another audio modem library to file away"
- "aww, I wonder what the details are... but that's a story in itself, alright then"
- "wait that says in production. this is actually keeping something standing up. Oh. I wonder if the recipient actually realizes."
So, the one question I probably *can* ask: what effective data rate did you manage?
Shielded cable was long enough to reach a separate isolated room, and easily unplugged by an operator when not in use.
USB wasn't considered secure enough, other forms of sneakernet were avoided for *reasons*. Alternative options could have been used but this was simple, auditable and (comparatively) easy.
Stakeholders fully aware of how it works and the weirdness factor. Not many users, and no scale involved. It just met a very niche use case nicely :-).
Hope that didn't dispel the magic for you.
Thanks for the extra details, that's really cool :)
echo "hello hacker news" | minimodem --tx 110
Even in a controlled setting the bitrate we achieved was very low, but for most songs it was enough to encode the lyrics. Seems quite useful until you remember both ends already need the original audio file in its entirety!
That still seems quite useful. Steganography aims to obfuscate the presence of communication, not encrypt the data. You'd embed your ciphertext via the audio steganography. I can imagine this used for a dead drop by placing the encoded audio in a jukebox, or potentially even playing it over the radio/muzak system, if that isn't too lossy / the algorithm has enough error correction.
Does anyone know what I'm talking about? Some of the demos sounded like R2D2 but also carried data. I can't find it using a Google search.
I think the researcher I had in mind was funded by Microsoft, or worked for Microsoft? They sounded like little robotic bird calls or something.
It's like Chirp.io took a single example from that paper and used it exclusively.
Created a new issue: https://github.com/martme/webaudio-modem/issues/8
Using the Web Audio API to Make a Modem - https://news.ycombinator.com/item?id=15471723 - Oct 2017 (63 comments)
a = "00FF AA 44 CC" * 100
!echo "$a" | pbcopy
Layer and phase shift to taste.