Roger that!
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Laser has much higher bandwidth, although you need to know roughly the direction/location of the recipient. And also has the advantage that it’s harder to listen in on.
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you can, depending on the design and sophistication of the receiver. The local oscillator signal can leak through the antenna interface of the radio and be detected by “authorities” . The resulting signal may be modulated by the actual station you are receiving revealing what you are listening to…also, one could infer the station you are tuned to by measuring the frequency of the local oscillator and applying the likely intermediate frequency offset. I believe this may have been used to enforce compliance with radio taxes in countries that had such things, as well as of course to hunt down spies (or freedom fighters, depending on your point of view ).
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Why did I ever get rid of my trusty Heathkit crystal set?
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PS:
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Can’t lasers be tracked to their source?
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IIRC similar Twitter accounts have allegedly been used in the United States for illegal communication (“co-ordination” being the legal term) between political candidates’ campaigns and supposedly independent PACs.
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And, maybe most important for covert stuff, the recipient is totally and completely untraceable. Just a thought.
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And in the video they posit that they still exist as a fallback position if digital communications go down.
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not unless you are in a position to intercept the beam, and then you only get a direction, not a distance
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They keep them going for the time travelers.
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If they only broadcast numbers when there was a message to transmit, they’d be giving up way too much information. So they’re undoubtedly broadcasting random filler numbers in between the real stuff.
And the same idea applies even if its years between actual messages. They still need to keep broadcasting nulls if they ever intend on using that channel again in earnest.
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Of course nothing prevents an electronic implementation of a one time pad. The problem with ANY private key encryption (like an OTP) is that you need an alternate, secure way to distribute the key. This is compounded in an OTP by the fact that the key is as long as ALL of the messages that you intend to send. OTOH, one memory stick can hold all the key that you will ever need, unless you’re encrypting video.
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An even better/worse example, back in 2010 CIA’s whole China network got rolled up and executed after China penetrated CIA’s covert communication network.
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There’s a trick, used in WWII to find people listening to the bad stations. A superheterodyne receiver has a Local Frequency Oscillator, usually tuned 455 KHz off the radio station frequency. It mixes that with the radio signal to get an intermediate frequency that can be filtered and amplified, then turned to audio.
Unless the radio is very well shielded, it’s going to leak a little of the LFO signal. A sensitive detector tuned to that frequency would find it, but only at close range. (It’s more for finding radios tuned to the BBC than a solitary spy.)
Heh, even if you don’t have spies listening for number stations, it’s a great trolley for making the other side think you do.
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I’m sure that it is actually the world’s longest game of Bingo. One day, someone will yell, “House!” and it will all start all over again.
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One-time pads are good, but it’s absolutely secure only if you keep the one time pad a secret between the sender and the receiver. Reading it out over the radio is kinda not-secret.
There is a really neat idea of using variations in pulsar frequencies as a number station for encryption.
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