Slashdot Mirror
Numbers Stations Move From Shortwave To VoIP
IO ERROR writes "For decades, intelligence agencies have been sending secret messages to their agents in the field using shortwave numbers stations broadcasting encrypted messages for all to hear and puzzle over. Now someone is putting numbers stations on VoIP telephone numbers for anyone to call, and posting messages to Craigslist to alert the recipients to the existence of their messages. One of them went up last month and now a second one has appeared. Will there be a third? Who's behind them? And can you crack the code?"
I know it's the first thing that comes to mind but I'm sure They can monitor who calls ("tunes into") that phone number regularily. Broadcasts are anonymous and many people own shortwave radios, VOIP can be traced to a subscriber so what gives?
The point of shortwave is that you can listen from anywhere, undetected.
Calling a phone leaves a bunch of traces. There is really no discreet way for our man in Havana to call longdistance and listening to numbers for a few minutes.
You could just put the numbers on a free website somewhere, or use email..
I'm not sure about that. VoIP has an unrelated and legitimate commercial interest behind it to support it not being blocked solely based on the virtue of it being VoIP, and thus anybody wanting to jam/block particular VoIP calls would have to know ahead of time at what phone number the message was going to appear. And there are a lot of phone numbers ;)
On the other hand, the various intelligence services have some pretty powerful jamming equipment that can render shortwave transmissions at least partially unintelligible. Numbers stations often work based on a schedule (in terms of both time and radio frequency), and once an intelligence service determines this schedule, they can wash out the frequency with crap at the appropriate time. Since the whole reason for numbers stations are that spies in the field are relatively incommunicado with their handlers, figuring out the schedule can have a fairly long-term impact on the spy being able to receive information and orders. In fact, the biggest question is likely where the jammer antenna should be positioned to ensure that the transmission will be jammed.
Very likely you can't easily crack the code. reason: it's a true code, not a cipher. A real code assigns a symbol like '34187' to a word or phrase arbitrarily. Unlike ciphers, true codes are very difficult to crack without getting the key somehow, because there is very little redundancy to exploit statistically.