Encryption Is Already Legal, It’s the Intention That’s Not

Fresh from the Unless You’ve Been Living In a Cave, You’ve Heard of This department, there’s been much ado over the FCC Petition for Rulemaking seeking encryption for emergency communications.  I won’t go into the details of the petition as you can read that several places elsewhere.  Technically encryption on amateur radio bands is illegal.  However, in reality the FCC has been letting it happen for years and the ARRL has turned a blind eye to it.  D-STAR uses a proprietary vocoder that takes an analog voice signal and converts it into a data bitstream.  The algorithm isn’t publicly documented and you can’t decrypt it, unless you buy a proprietary chip.

Some may quote § 97.309 (4)(b) which basically says one can transmit an “unspecified digital code” as long as the digital code is not intended to obscure the meaning of the communication.  Presumably the people who created and use D-STAR don’t intend to obscure the meaning of the communication, so perhaps it is within the law.

So, say I create a new digital communication mode.  It features a compression algorithm and I just happen to XOR the data stream with a 10 million bit pseudorandom bitstream to randomize it so a long stream of zeros or ones won’t screw up a modulator.  I document the algorithm and the 10 million bit key on some corner of the Internet.  It’s technically publicly documented, but in practice no one will go to the trouble of attempting to build a decoder.  I’ve achieved encryption in a roundabout way.  Whether my intentions were to obscure the meaning of the communications or make a modulator-friendly bitstream is anyone’s guess.  But with the inaction over the D-STAR vocoder and the wording of § 97.309 (4)(b), intention rules the day.  So while this debate over the petition is being framed in a discussion of encryption, it’s really the intent to obscure communications that’s at the heart of this.

I don’t have a horse in this emcomm race, but I’m not in favor of allowing obscuring messaging.  If the FCC does allow it, others are going to want to use it for their noble causes, like preppers under the guise of “homeland security”.

(D-STAR is a registered trademark of Icom, Inc.)

Anthony, K3NG, is a regular contributor to AmateurRadio.com.

9 Responses to “Encryption Is Already Legal, It’s the Intention That’s Not”

  • Jason ke7tdy:

    WOW, you make a GREAT point I overlooked in stating my support for encrypting EmComm tx.
    I never considered the D-Star [which I dislike, but not for that reason] encryption …
    Thanks for mentioning that 🙂
    73
    ~J

  • W9VHE:

    The above point makes a good reason for other manufacturers (or those talented folks that make the great Ham Radio software) to develop further digital voice modes, not just for hams with deep pockets, but the average ham operator.

  • W9IQ:

    The algorithm used in the D-Star chip is a matter of public record, fully disclosed to the patent office. You can duplicate the algorithm – but commercial use of it is prohibited by patent law, not the FCC. Further the use of the algorithm is not to obscure the meaning of the message but to compress audio. This is also clear by the patent and by its application in the D-Star standard.

    If you create and use an algorithm whose purpose is to obscure on the ham bands – good luck with the FCC.

    – Glenn W9IQ

  • Glenn, I’m going to invoke the “citation please” option. What is the patent number and where is the documentation sufficient to duplicate the algorithm?

  • I should add I did do a cursory search on Google patents for this and didn’t find it. Regardless, I doubt there’s public documentation on the algorithm, otherwise there would be an open source implementation of it.

    The D-STAR situation shows that obscuring encryption in practice is permissible. If I make a black box to decode the transmissions and create some sort of artificial scarcity (i.e. high price or limited availability), it’s still decodable like D-STAR. Proving intent to obscure is another issue.

  • W9IQ:

    Try looking at US6199037 et al and you will find the background. There is significant documentation within the patent. You will find it very difficult to create your own version of the CODEC but that is an issue of work effort – not of availability of the algorithm.

    The question of encryption is not tested by whether or not there is an open source algorithm. The question, in the context of part 97, is “purpose”. Clearly the purpose of the AMBE algorithm is not to obscure the voice transmission but to digitize and compress it.

    It is fair to argue whether or not D-Star should have used a license free or free license CODEC but it is technically flawed to argue that it is encryption in the context of part 97.

    Your use of the term “obscuring encryption” is not a valid term in the field of cryptography. The only purpose of encryption is to obscure the content of a message. Therefore the term encryption stands alone.

    – Glenn W9IQ

  • I see there is a lot of information in the patent. Thanks for locating that and posting it. I still doubt anyone could make their own implementation of it. The documentation lacks some specific implementation details, devil-in-the-details minutia like administrative bits. Undoubtedly someone would have to do a lot of “cut and try” interfacing with a real AMBE chip to determine if they got it right.

    I’ll agree the term encryption implies obscuring. Perhaps a better term I should use is encoding. Encoding is legal. And it’s technically feasible to make it impractical and nearly impossible to decode, and stay within the rules. The intent in this petition before the FCC is very clear, it’s obscuring the message. For those people not so open about their intents, there’s plausible deniability.

  • W9IQ:

    I agree the petition is all about encryption in the strict technical sense of the word. In my response to the FCC, I asked that they clarify that the use of encryption is synonymous with the “purpose to obscure”.

    The use of encoding is legal within limits. Part 97.309(4) makes it clear that any encoding methods “whose technical methods have been documented publicly” for the purpose of “facilitating communications” may be used. This negates the possibility of legally using an algorithm to transmit under part 97 that is impossible to decode.

    – Glenn W9IQ

  • N3GWG:

    Anthony, Glen, et alia:

    I am not a lawyer and I don’t play one on TV, but as a Computer Scientist, I do know a little bit about logical thinking and from experience I know how the courts work (from reading, listening, observing and participating in their activities).

    Where a government agency does not define term in promulgated rules (or Congress does not with respect to legislation), the Supreme Court and many other inferior courts usually start with the dictionary definition of a word or phrase before their analysis begins. In the instant case, it would seem that “obscure” (taken as a verb) has several meanings, the most sensible for our purposes (as depicted by the Oxford Dictionary website) is:

    “Make unclear and difficult to understand”

    Now, before I continue, I would absolutely suggest that in the absence of a definition for obscure in 47 CFR Part 97 definition list, that should be the first “rule change” we request from the FCC (the addition of a definition) before any other portion of the 47 CFR Part 97 rules are even contemplated or capable of being understood. Absent a definition, obscure can mean many things and is open a rather broad interpretation.

    In this context one could argue that using Q codes (QST, QRT, QRP, etc.…) is obscuring the meaning of communications since the common person has no clue what those codes mean. It may well be the position of the FCC that it is irrelevant that the codes are published and that only the intention to obscure the meaning is required to be judged as acting contrary to Part 97. Moreover, with ease of putting a website today and its relative low cost of entry, publication is rather easy to do.

    Moreover, what if we used words and language that only 1/100 of 1 percent of the world’s population could understand? So, if 5 million of 5 billion (I think the world population is closer to 6B or 7B people, but I used 5B for mathematical simplicity) people could understand something, would that be obscuring the meaning? If so, clearly speaking Hebrew on the Amateur Bands violates 47 CFR Part 97 then, right? Obviously identifying would need to be in English.

    Secondly, a new mode that happens to be expensive, unpopular or require a proprietary chip does not in and of itself make the mode “obscuring” in nature, since anyone can ostensibly acquire the requisite technology in pursuance of decoding it. The fact that any particular Amateur Operator cries over the price tag is simply not relevant at all as I see it. I believe and have always understood the FCC’s meaning to be not some new mode that you do not own the decoder for, but encryption technology specifically. Since by some broad sweeping definitions that suggest new modes are obscuring in nature as some of the posters have suggested we would be left considering if not just DSTAR but DMR, Fusion, and P25 on the Amateur Bands would all be problematic, something the FCC has shown no concern for by its inaction over the course of numerous Presidential administrations allowing digital voice transmissions. Moreover, the development of new digital technologies is one of the rooted purposes (experimentation in general) of Amateur Radio and as such would seem particularly curious for the FCC to wish to impede.

    Granted, one can argue that the FCC intentionally means more than encryption (obscuring being a broader term) or they would have used alternative English construction and vocabulary, or provided a more narrow definition in the rules. As such it may be inferred that the word obscure could be interpreted to mean an enumeration of different things, including a new spoken language meant only for use by Amateur Radio Operators during emergency communications. Would that be illegal too?

    I think that having a broad less narrow and clear definition of obscure in 47 CFR Part 97 gives the FCC what it wants, the ability to interpret the phrase “obscuring communications” however they wish when they feel they need to in the absence of being accused of providing Amateurs with no forewarning of the rules.

    Very Respectfully Submitted,

    Stuart B. Tener, N3GWG
    Computer Scientist

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