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Comment by fest | Hacker News Reader

I hope the next revision of MAVLink (one of the most common message serialization/transport protocols used for UAVs) will have built-in encryption.

While systems can encrypt MAVLink messages in transit, I have not seen it actually done- everyone is relying on security of the physical layer (i.e. obscurity of telemetry radio frequency hopping/channel negotiation, WiFi security).

So in most implementations, MAVLink messages are actually transmitted in plaintext, over plain TCP/UDP connections.

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Many of these systems are using the amateur radio service bands. Often 5GHz for video, 2.3-2.4GHz for control and telemetry and less frequently 1.2GHz, 900MHz and 70cm are also used. The FCC doesn't allow encrypted traffic on amateur bands except for specific cases such as satellite telecommand. I suppose that has discouraged adoption of cryptography.

What are commercial operators doing? Another limitation of Amateur bands is that they can't be used for commercial purposes, so licensed commercial drone operators must be using commercial bands where cryptography is permitted. Don't know myself; haven't looked into it.

> Another limitation of Amateur bands is that they can't be used for commercial purposes, so licensed commercial drone operators must be using commercial bands where cryptography is permitted.

I don't think so. I think we can agree that many, many commercial operators use DJI. There are also lots of amateurs using DJI. Both use the same firmware. There is no option for me to encrypt or unencrypt my Phantom which I could easily use commercially if I had my FAA Part 107.

I see. So they're operating in the ISM portion of 2.4 and 5GHz. In that case they can encrypt. So the original question seems a good one; why haven't they yet?

My understanding is that there is an exemption in amateur radio for model aircraft control signals that allows encryption [1].

[1] https://www.govregs.com/regulations/title47_chapterI_part97_...

> The FCC doesn't allow encrypted traffic on amateur bands

Would traffic that is not encrypted but is instead authenticated (with a MAC tag or AEAD'd) be allowed? What are the exact FCC rules and laws at work?

In our product "Sky Drone FPV" we encrypt the MAVLink channel via DTLS.

Cool, kudos for taking a responsible approach!

I understand it might be a trade secret, but what LTE modem do you use on receiver side? I would like to use LTE more, but finding suitable modems for embedded uses has been a challenge.

True, LTE modem protocols are a bit of a mess. You can get a good overview here: https://aleksander.es/data/FOSDEM2013%20-%20Mobile%20broadba...

We're working on this at CryptoMove: https://www.dhs.gov/science-and-technology/news/2017/03/29/n...

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