> "I'm sure that even before LLMs one could find a way to create a story where certain numbers / code words would be embedded without altering the underlying story too much."

It's called steganography, and it's a centuries if not millennia old technique.

Seems to me like coordinating with an entity outside of the spooks' control, such as the BBC, would give more opportunities for leaks. It would also reveal some information about who is controlling the signal--someone with some kind of relationship with the broadcaster.

who's to say they aren't doing both? They may not even be sending anything over the number station; these stations will continue on a schedule even when there is nothing to say and nobody is listening because it makes it harder to eek out a foothold in the event of a weakness in the encryption.

Shortwave propagates better and also its just a one time pad being distributed so embedding doesn't matter as much as long as the one time pad is longer than the intended message to send. There is no way to decrypt it because once you encrypt a message using a one time pad it is impossible to decrypt without the exact one time pad that it was encrypted with.

I think you're massively overestimating the amount of control the US has over news broadcasters.

I can't find it immediately, but I've read about something even sneakier than this. A standard broadcast station was modified such that its carrier signal was modulated by a PSK signal. The intended listener would use e.g., a PSK-31 modem to listen to the carrier signal and would be able to obtain the encoded digital data. Everyday listeners would hear the regular broadcast. The station involved _might_ have been a BBC station, but I don't recall.

The previous time that the US and UK overthrew Iran's government (https://en.wikipedia.org/wiki/1953_Iranian_coup_d'%C3%A9tat), they used the BBC in that way.

  Roosevelt told the Shah that he was in Iran on behalf of the American and British secret services, and that this would be confirmed by a code word the Shah would be able to hear on the BBC the next night. Churchill had arranged that the BBC would end its broadcast day by saying not 'it is now midnight' as usual, but 'it is now exactly midnight'

I think they do this, too.

However, the numbers stations transmissions are never a big secret. They're intentionally powerful so someone can pick them up on simple equipment without raising suspicion. A person can modify an off-the-shelf AM radio to pick up shortwave, for example, even in an oppressive regime.

It's a one-time pad, so the encryption is unbreakable.

regular AM/FM stations are not broadcasting on shortwave bands

Shortwave radio is more challenging than you might imagine.

Near to the transmitter it's received by ground wave, further it's scattered off the ionosphere. In-between it's undetectable due to the skip zone. This might also explain why Amelia Earhart went missing [1]

Coverage is obtained from multipath and reflections. Leading to variable strength and timing. Not as bad as DXing on HF with low power but much harder than you might imagine.

Fine for someone to transcribe some numbers but useless for people trying to identify sources.

So locally you get an apparent direction to the source which is clearly not the source.

Add to that the complex local terrain and a well placed number stations can be very difficult to locate with precision.

Edit: unrelated but interesting there are some mysteries in HF transmission including long delayed echoes where a signal takes far longer than reasonable to travel out and back over several seconds [0] which given its travelling light milliseconds is a conundrum.

[0] https://en.wikipedia.org/wiki/Long_delayed_echo

[1] https://youtu.be/zTDFhWWPZ4Q?si=Ib8jfbdNP-sLHM0B

The broadcast locations aren't really secret, and don't need to be.

Street View nearby reveals this sign at the edge of the Street View area: "Forstarbeiter und Militär Frei," which means "Forestry Workers and Military [are free to enter]". The red circle around the sign implies that everyone else is forbidden to enter. So, it's some kind of military installation.

Neat, there's no Street View coverage but there is clear sattelite imagery: https://maps.app.goo.gl/RjGUAMExUrD6aqs59

Apple's maps version has that section blurred out though.

Bing's sattelite images seem to be older, the antenna isn't visible on there yet and there's just building foundations: https://www.bing.com/maps?cp=48.690103%7E9.086240&lvl=18.8&s.... Can't determine how old those images are though.

These two don't have to be related per se, but it sure helps with maintaining a healthy mutually beneficial military relationship.

Interesting. I have no reason to disbelieve you.

So...

If its being broadcast by the US military or the CIA, why Persian?

Because they're issueing activation orders to their network of ani-regime operatives inside Iran? Who, mysteriously for spies, only know that language?

Or because they want the Iranian government to think that? And a numbers station broadcasting in - unusually - Persian, is an easy way to get the attention of the Iranians?

I'm thinking the latter.

Thanks for the link, really interesting!

It’s simple, reliable, and effective. Shortwave receivers can be made fairly compact. They’re also very prevalent in most countries (every ham transciever), so there’s nothing suspicious to pack. People find numbers stations interesting, so they are often streamed online. One time pads have their logistical shortcomings, but are still the best encryption possible. The OTP can be compromised in known, visible ways, where a phone has myriad invisible ways to be compromised.

Like the article says, satellite messages can be traced while radio is broadcast to everyone so it's impossible to find out who's listening. Shortwave radios are also cheap and widespread, so it's easy to get one anywhere in the world and if your house gets searched, it won't be suspicious if you have one.

Phones usually contain the hardware for radio too, so making sure agents have some set of models for that doesn't sound bad. Even if you had to use a dedicated one having a radio at home isn't that conspicuous? Or in a car, etc

perhaps they're not directed at deeply embedded lone spies with radios in their attics, but at 'military assets' which as a matter of course can receive these transmissions on a designated schedule.

Ok, we've changed to that from https://www.wired.com/story/a-mysterious-numbers-station-is-... above, and I've put the latter link in the toptext. Thanks!

I've been off put by WIRE recently. Thanks for this.

> Sifr is also a valid word both in Farsi, I think

That is the root of 'cipher'; meaning zero/empty/nothingness.

More so if you know the etymology,

https://www.etymonline.com/word/cipher

(Al Jabr, the translator of Indian Mathematical texts was a Persian IIRC)

Random chance has a really good sense of humor!

1/10 dentists hates nominative determinism. That dentist? Dr. Procter

You'd be amazed how many firefighters I know called "Burns", even leaving aside Ayrshire where lots of people are not-too-distantly related to a famous poet who, to put it mildly, put it about a bit.