Random numbers, Persian code: A mysterious signal transfixes radio sleuths

Post by user982 » Wed, Apr 01, 2026, 7:37 PM UTC

NitpickLawyer wrote: post #12

I wonder why they keep using a dedicated numbers station instead of embedding the code in a regular radio broadcast on a traditional channel? 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. And they could probably get BBC / whatever station to air it. It would be a bit less inconspicuous to liste…

  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'

Post by teeray » Wed, Apr 01, 2026, 7:57 PM UTC

smegger001 wrote: post #80

teeray wrote: post #9

Earlier quoted context omitted.

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, wh…

You could probably cheat with the one time pad and use a book as a key, pick a pre determined starting point go diagonally down accross the page convert the letters to numbers and xor that against the message. It would be near enough to random and less conspicuous than a pad of random numbers when searched.

Post by red_admiral » Wed, Apr 01, 2026, 8:09 PM UTC

b00ty4breakfast wrote: post #37

NitpickLawyer wrote: post #12

I wonder why they keep using a dedicated numbers station instead of embedding the code in a regular radio broadcast on a traditional channel? 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. And they could probably get BBC / whatever station to air it. It would be a bit less inconspicuous to liste…

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.

Post by red_admiral » Wed, Apr 01, 2026, 8:17 PM UTC

rustyhancock wrote: post #14

srean wrote: post #7

Does this move around geographically ? Triangulating broadcast location is a well understood craft.

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 t…

Post by bell-cot » Wed, Apr 01, 2026, 9:01 PM UTC

BenjiWiebe wrote: post #72

pclmulqdq wrote: post #67

Earlier quoted context omitted.

Every message is equally likely when you attempt this kind of brute-force decryption with a one-time pad. The code you get is actually 100% unbreakable if the pad isn't intercepted.

I think there's some confusion in this thread. GGP talks about distributing the one time pad via the numbers station. GP (rightly) says that's a stupid idea. The numbers station should be transmitting a message encoded with a one time pad. The one time pad itself should be physically given in person to the spies who you want to communicate with.