Encrypt file

>encrypt file
>add powerful error correction
>use steganography to hide in picture
>use legit ham callsign to transmit picture via sstv on hf
Does this mean you can use encrypted comms completely legally?

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Other urls found in this thread:

radioexperimenter.us/rm-1972-01/v-ham.html
barberdsp.com/files/Dayton Paper.pdf
twitter.com/SFWRedditImages

Are you implying encrypted communications over the Internet (PKI, etc) are illegal?

Only in the sense that it's not illegal if you don't get caught. Nobody except hams cares about the ham bands.

>encrypt
Already illegal bro.

Im talking about radios and shit
I dont see why it would bother anyone.You'd be using a channel's redundancy that'd be wasted anyway.

I think hammies might track you down
Those guys are the janitors of the airwaves

But what if I were a ham and I sent said picture to other legit ham? Nobody but recipient would even know that there's a hidden file in the picture.

Nobody knowing is not the same thing as it being legal.

Tree falls in the woods etc.

I don't see how an SSTV image could still contain the stenographed information.

It's an analogue transmission of an image, and only the image without anything else.
If there's any disturbance in the signal (which there is over a long distance transmission without Megawatts of power) the picture contains a lot of noise.

So not only would SSTV be the totally wrong method for doing this, it's also fairly unreliable for this type of stuff (the human brain can correct the lost information in an image)

What you're looking for might be something like PSK1000 or Packet Radio

That's where error correction comes in. Add somethig as powerful as turbocodes or a gigantic hadamard code and you could extract data from a turd thats been floating in a river for a month.
Im interested in sstv because its the only mode to offer a reasonable amount of redundancy. Purely digital modes are too efficient and theres nowhere to hide the data.

but in that analogue transmission mode there's nowhere to put the data. .... unless you transmit QR- or DataMatrix-Codes .
It's purely analogue. There were devices with memory Tubes (CRTs that display a slowly reproduced image for a longer time (which was a purely physically effect that dodn't involve any memory electronics)) when SSTV was invented.

radioexperimenter.us/rm-1972-01/v-ham.html

Today we reproduce this behavior (even with color) in HAM software, but it's still onyl an image with no header (other than the FSK header sequence which identifies the SSTV-Mode which is used) and an end sequence.


How would you add stenographed informatio to this picture?

Data would be hidden in the lsb's of the pixel values.
The recipient would have to have the original image. He could then compare the received image with the original,and then he'd use soft decision decoding to extract the data. The images would have to be perfectly aligned though. I'll try to do some experiments but I think it should work as long as there's not too much noise.

SSTV is FAR too lossy for this kind of thing.

SSTV only transmits image data, so your data would have to be part of the image itself.
Any form of image manipulation of the image subtle enough to not be visible to your naked eye would be completely washed out by the time the image has been transmitted and decoded.

Furthermore, the highest resolution offered by any SSTV mode is 256×256. The amount of data you could fit on there would be abysmal.

You'd have to use special software to extract the data.
I know it's not exactly practical for transmitting anything beside short text messages, but idk if there's any other mode that could be used for steganography especially on hf.

This. Hams are turbo cucks. They love licking FCC's boots.

Just use OTP encryption you turbo autist.

Nigga I'm talking about a 100% deniable communications channel. Encryption is just a tiny part of it.

>it's illegal to send a stream of random 0's and 1's

Just say it was a random number generator.

Gibberish would attract attention.

Ill see if I get any attention if i stand on a podium in the town hall and just talk gibberish over a PA-system .. oh wait in the united states this does attract attention and is proven to be a feasible way to become the president.

You can't store a reliable error correction that will compensate for the noise in a 256x256 image.

If it's in the LSBs would he even need the original as long as he knew the first and last byte of the image where the stego'd file was described?

Idk man,error correcting codes have come a long way. There are plenty of rf schemes that go ridiculously low under the noise floor.

Simply decoding it could be problematic since the sstv decoder simply measures the frequency of the tone and decides the pixel value based on the frequency. All sorts of propagation effect could completely fuck up the lsb's. My idea is to compare the ideal waveform (original image) to the received waveform (received image) and measure the differences in every predetermined bit position. Soft decision decoding could then try to extract the data if enough of it remains.

No.

Just use a qr code

QR codes can have up to about a 40% error recovery, but a 125x125 code can only store about 625 bytes at that level of error correction.

a 125x125 QR code would fit into a 256x256 SSTV image, making each QR code pixel display as 2x2 pixels on the decoded SSTV image.

Options for a 256x256 resolution SSTV transmission are Martin 2, Robot 72, AVT 32, AVT 48H, AVT 104, or either of the Scottie modes.
The fastest of these options is AVT 32, which takes 32 seconds, and is B&W only, so this will work well for a QR code.
This means your maximum bandwidth for encrypted data would be 625B/32s= 19 Bytes/Second.

You would be better off using PSK31.

That one was r36, and the qr code is perfectly legible. But yes, you're better off modulating the data directly to PSK RTTY instead of SSTV.

That's also only a 37x37 QR code, meaning you took 4 seconds longer to transmit ~560 bytes less data.

There's really no way to transmit any meaningful amount of stenography data over ham radio.


Also, does anyone know why it's illegal to transmit encrypted data over ham bands?
I can't think of any reason other than the fact that ham bands are a public domain.

>Also, does anyone know why it's illegal to transmit encrypted data over ham bands?
They probably don't want large companies and organizations using public bands. Would mean less money for governments.

Yeah, that's the best I could figure.

As long as we're talking SSTV, does anyone have any good sources for mode specifications?
I want write my own SSTV encoder/decoder.

So far this is the best I can find: barberdsp.com/files/Dayton Paper.pdf

Because of the loss I think you'd have to use something highly inefficient. Like displaying a "static" image which is only perceptibly static, in reality you'd be changing the sten data each frame and most of the storage you have would have to be used up on parity blocks or whatever redundancy solution you come up with. I wonder if you could even do it in a way that wasen't perceivable visually, and going beyond that, avoiding some kind of signal pattern detection as well.

Seems plausible but not practical, neat idea though.

Similar to like a modem or some shit.

This guy hams.

>It's illegal distribute naked pictures of people who have existed for less than 18 full orbits of the earth around the sun

>certain combinations of organic matter and planetary orbits are illegal

Except HAM radio is literally a tree falling in the middle of the city.

>analog
>0s and 1s
Encrypted comms on HAM radio is illegal in the US for some reason.

This a real fucking interesting thread.


How is the radio scene so cucked by the FCC?

boomers are robotic unfeeling puppets. Lapdogs to the CIA

and millenials are obsessed with muh feefees, lapdogs to faux political movements controlled by the CIA
you can't win

pussy

It's really not.

Ham radio has the largest range of frequencies allocated to it, short of the US military.
There are, however, lots of rules to make sure that those frequencies remain clear and free of noise.
It only takes one asshole with an amp to render a whole band useless.

Encryption was banned far before personal computers were really a thing.
Encryption being banned is a rather outdated rule though, although it does still have a few reasons for existing.
Originally, encryption was banned to mitigate any espionage during WWII.
Currently, it serves to deter private use of frequencies, since the ham bands are a public resource.

Honestly though, I don't think you'll get anything more than a slap on the wrist currently if you send encrypted data over digital modes.
Just a "Hey, stop doing that because it's just noise to the rest of us."

That said, if you continually broadcast encrypted data for an extended period of time you might get into some trouble.

wow you sure told him user wew

you his boyfriend? faggot.

Because you have to appease the FCC to keep them from taking your ham frequencies and auctioning them off to Verizon.
FCC says no encryption? Hams will make a serious effort to track down and report offenders, to keep the FCC from going "oh well you guys can't follow the rules, we'll give the spectrum to someone who will".

Also it's super easy to triangulate radio transmissions, as opposed to the internet where the source of data can be easily masked.

what a convincing argument

you have no balls.

>implying the FCC won't sell the frequencies anyways when the money comes calling and just put some vague excuse for it anyways
ham niggers deserve to get shot

I'm your keeper, you little bitch nigger.

Who let the reddit kid out of his cuckbox?

you're a pussy.

Has anyone ever been talked to by the FCC for encrypted communications over HAM?

I fucked yours, faggot.

look at you. you're gay.

keep projecting.

listen, you're not fucking anything. you're just really gay.

>obsessed with muh feefees
This is actually boomers as evident of the policies they vote in.

Bumping for more information on this.

Except we have a pretty powerful lobby called the ARRL who sets up agreements with the FCC to keep that from happening.
But no, I'm sure you'd love for the only free long haul radio communication platform to be sold off to the latest meme company so they can sell you data capped cell plans.