4 ms·

Could you hide an encrypted signal in what appears to be a normal HAM radio signal? I know it would be illegal, but is it possible?

refuse 4y ago
Steganography? Sure, but you might be better off using a code that sounds like normal speech.
- godelski 4y ago
  There's a lot of weird stuff on radio. You don't need encryption to have codes. But this probably wouldn't be useful for sending surveillance information from a balloon. It would also draw a lot of attention. https://en.wikipedia.org/wiki/Numbers_station https://en.wikipedia.org/wiki/Numbers_station (Buzzer) https://en.wikipedia.org/wiki/UVB-76 https://en.wikipedia.org/wiki/UVB-76 https://en.wikipedia.org/wiki/Secret_broadcast https://en.wikipedia.org/wiki/Secret_broadcast
maxbond 4y ago
Edit: I think I got confused by reading an article a long time ago referencing the command & control exemption mentioned in another comment. I should've kept my mouth shut about a legal matter I couldn't properly articulate/didn't fully understand or at least put IANAL, my bad. --- original comment: --- This regulation is often misunderstood. The requirement is that it must be possible to decode the signal; the signal cannot be scrambled. It is totally legal to, for instance, have an HTTPS connection tunneled over an internet radio link, as long you could decode the radio message - it's not illegal for a message to carry an encrypted payload. By the same token, steganography wouldn't be illegal either. This regulation isn't trying to stop you from sending secret messages, it's making it possible to introspect the messages to determine what protocol and call signs are involved. It's about managing the spectrum and figuring out who to complain to if there's interference, not about controlling cryptography.
- detaro 4y ago
  That's wrong. The prohibition is exactly on non-understandable meaning of messages, recognizable protocol and call signs is not enough.
  - MandieD 4y ago
    It’s also part of why a lot of amateur radio-related sites still serve unencrypted HTTP, either optionally or exclusively. (The other part of why is that there are an awful lot of valuable amateur radio sites that haven’t been updated in 15-20 years)
    - detaro 4y ago
      or are ran by people who can't be bothered to figure this new-fangled HTTPS stuff out
      - LarryMullins 4y ago
        Or people who buy into the "nothing to hide" nonsense, influenced by a HAM culture of not encrypting things that emerged from the rule against it.
  - maxbond 4y ago
    [dead]
- progman32 4y ago
  Can you post a citation for that? Everything I've heard indeed claims that any encryption is no go except for a narrow band of critical applications.
- teraflop 4y ago
  FCC regulations say: "No amateur station shall transmit: [...] messages encoded for the purpose of obscuring their meaning". https://www.law.cornell.edu/cfr/text/47/97.113 https://www.law.cornell.edu/cfr/text/47/97.113 This isn't entirely unambiguous, and people can and do argue about how it applies to things like proprietary data protocols that aren't publicly documented. But I think it's clear that encryption, such as that used by HTTPS, is intended to be banned by this clause.
klyrs 4y ago
With steganography[1], it's certainly possible. For instance, if your balloon is only broadcasting its location, you can fuzz the highest precision bits of the longitude and latitude to emit a few bits of signal at a time. Or, for example, you can oversample from a GPS satellite, and only broadcast the locations whose high-precision bits match the signal you want to broadcast. I do think this would be illegal, but detecting it could be quite difficult. [1] https://en.m.wikipedia.org/wiki/Steganography https://en.m.wikipedia.org/wiki/Steganography
- flavius29663 4y ago
  I still remember the project in college where I embedded quite a lot of information in images. While detecting would be difficult, if NSA puts its mind to it and figured it out, then it would be very clear what you were doing, you can't claim randomness in your defense
  - klyrs 4y ago
    Yep, the detectability of steganography tends to increase with information density, of course. If somebody is watching GPS traffic they could discover my (hastily conceived) location-beacon scheme, for instance. Likewise, a metadata scheme (varying time between broadcasts) could be discovered through close enough examination. But, that at least has some plausible deniability baked in, random delays are better than fixed delays in terms of network congestion.
    - flavius29663 4y ago
      That was my point, there is no plausible deniability. Your cleaned-up data just happens to be the png image of some secret US bases? Good luck convincing a judge it's not intentional. If you encrypt it well enough, it might be that NSA never discover the underlying data, but that hinges on protecting the emitting source. If they get their hands on it, they can recover the keys.
  - LarryMullins 4y ago
    The NSA might figure it out, but I doubt they'd tell the FCC about it.
deleted 4y ago
[deleted]

refuse 4y ago

Steganography? Sure, but you might be better off using a code that sounds like normal speech.

godelski 4y ago
There's a lot of weird stuff on radio. You don't need encryption to have codes. But this probably wouldn't be useful for sending surveillance information from a balloon. It would also draw a lot of attention. https://en.wikipedia.org/wiki/Numbers_station https://en.wikipedia.org/wiki/Numbers_station (Buzzer) https://en.wikipedia.org/wiki/UVB-76 https://en.wikipedia.org/wiki/UVB-76 https://en.wikipedia.org/wiki/Secret_broadcast https://en.wikipedia.org/wiki/Secret_broadcast

maxbond 4y ago

Edit: I think I got confused by reading an article a long time ago referencing the command & control exemption mentioned in another comment. I should've kept my mouth shut about a legal matter I couldn't properly articulate/didn't fully understand or at least put IANAL, my bad. --- original comment: --- This regulation is often misunderstood. The requirement is that it must be possible to decode the signal; the signal cannot be scrambled. It is totally legal to, for instance, have an HTTPS connection tunneled over an internet radio link, as long you could decode the radio message - it's not illegal for a message to carry an encrypted payload. By the same token, steganography wouldn't be illegal either. This regulation isn't trying to stop you from sending secret messages, it's making it possible to introspect the messages to determine what protocol and call signs are involved. It's about managing the spectrum and figuring out who to complain to if there's interference, not about controlling cryptography.

detaro 4y ago
That's wrong. The prohibition is exactly on non-understandable meaning of messages, recognizable protocol and call signs is not enough.
- MandieD 4y ago
  It’s also part of why a lot of amateur radio-related sites still serve unencrypted HTTP, either optionally or exclusively. (The other part of why is that there are an awful lot of valuable amateur radio sites that haven’t been updated in 15-20 years)
  - detaro 4y ago
    or are ran by people who can't be bothered to figure this new-fangled HTTPS stuff out
    - LarryMullins 4y ago
      Or people who buy into the "nothing to hide" nonsense, influenced by a HAM culture of not encrypting things that emerged from the rule against it.
- maxbond 4y ago
  [dead]
progman32 4y ago
Can you post a citation for that? Everything I've heard indeed claims that any encryption is no go except for a narrow band of critical applications.
teraflop 4y ago
FCC regulations say: "No amateur station shall transmit: [...] messages encoded for the purpose of obscuring their meaning". https://www.law.cornell.edu/cfr/text/47/97.113 https://www.law.cornell.edu/cfr/text/47/97.113 This isn't entirely unambiguous, and people can and do argue about how it applies to things like proprietary data protocols that aren't publicly documented. But I think it's clear that encryption, such as that used by HTTPS, is intended to be banned by this clause.

klyrs 4y ago

With steganography[1], it's certainly possible. For instance, if your balloon is only broadcasting its location, you can fuzz the highest precision bits of the longitude and latitude to emit a few bits of signal at a time. Or, for example, you can oversample from a GPS satellite, and only broadcast the locations whose high-precision bits match the signal you want to broadcast. I do think this would be illegal, but detecting it could be quite difficult. [1] https://en.m.wikipedia.org/wiki/Steganography https://en.m.wikipedia.org/wiki/Steganography

flavius29663 4y ago
I still remember the project in college where I embedded quite a lot of information in images. While detecting would be difficult, if NSA puts its mind to it and figured it out, then it would be very clear what you were doing, you can't claim randomness in your defense
- klyrs 4y ago
  Yep, the detectability of steganography tends to increase with information density, of course. If somebody is watching GPS traffic they could discover my (hastily conceived) location-beacon scheme, for instance. Likewise, a metadata scheme (varying time between broadcasts) could be discovered through close enough examination. But, that at least has some plausible deniability baked in, random delays are better than fixed delays in terms of network congestion.
  - flavius29663 4y ago
    That was my point, there is no plausible deniability. Your cleaned-up data just happens to be the png image of some secret US bases? Good luck convincing a judge it's not intentional. If you encrypt it well enough, it might be that NSA never discover the underlying data, but that hinges on protecting the emitting source. If they get their hands on it, they can recover the keys.
- LarryMullins 4y ago
  The NSA might figure it out, but I doubt they'd tell the FCC about it.

deleted 4y ago

[deleted]