Tag Archives: Cuban Spies

Numbers station HM01…and Ana Montes

Wednesday morning, I suppose I had number stations on the brain. It was no surprise, as I had just watched The Numbers Station the previous night. Nonetheless, I experienced a rather strange coincidence: I was reading an intriguing article about Ana Montes, “one of the most damaging spies in U.S. history,” when my shortwave radio–parked on 5,855 kHz–suddenly began to fire out an eerie series of numbers and data bursts from the Cuban numbers station, HM01. It was, unquestionably, the perfect accompaniment to the words I was reading.

A reader sent Montes’ story–written by Jim Popkin for The Washington Post Magazine–which made for fascinating reading. And as I read the account of Ana Montes’ rise in the ranks of the DIA, while simultaneously becoming one of Cuba’s most important spies, I remembered that it was actually Montes’ case that reader Dirk Rijmenants’ referred to in his paper, and that we posted earlier this year.

A “cheat sheet” provided by Cuban intelligence that
Ana Montes used to help her encrypt and decrypt
messages to and from her handlers. (Source: FBI)

Popkin’s account of Ana Montes’ life, character, promotions within the Defense and Intelligence Agency, and the sequence of events that led to her FBI investigation and imprisonment, are the stuff of spy novels. And of course, he mentions numbers stations:

[Montes’] tradecraft was classic. In Havana, agents with the Cuban intelligence service taught Montes how to slip packages to agents innocuously, how to communicate safely in code and how to disappear if needed.[…]

Montes got most of her orders the same way spies have since the Cold War: through numeric messages transmitted anonymously over shortwave radio. She would tune a Sony radio to AM frequency 7887 kHz, then wait for the “numbers station” broadcast to begin. A female voice would cut through the otherworldly static, declaring, “Atención! Atención!” then spew out 150 numbers into the night. “Tres-cero-uno-cero-siete, dos-cuatro-seis-dos-cuatro,” the voice would drone. Montes would key the digits into her computer, and a Cuban-installed decryption program would convert the numbers into Spanish-language text.[…]

On a side note, as Rijmenants points out, using a computer to decipher a numbers station was both unnecessary and risky.

The story continues:

Ana Montes

[…]On May 25, 2001, [an FBI team] slipped inside Apartment 20. Montes was out of town with Corneretto [her boyfriend], and the FBI searched her closets and laundry bins, paged through shelves of neatly stacked books and photographed personal papers. They spotted a cardboard box in the bedroom and carefully opened it. Inside was a Sony shortwave radio. Good start, Lapp thought. Next, techs found a Toshiba laptop. They copied the hard drive, shut down the computer and were gone.[…]The documents, which Montes had tried to delete, included instructions on how to translate numbers-station broadcasts and other Spy 101 tips.[…][…]Later that day, an FBI evidence team scoured Montes’s apartment for hours. Hidden in the lining of a notebook they found the handwritten cipher Montes used to encrypt and decrypt messages, scribbled shortwave radio frequencies and the address of a museum in Puerto Vallarta, Mexico, where she was meant to run in an emergency. The crib sheets were written on water-soluble disappearing paper.[…]

The story Popkin recounts, though, paints the picture of a very complex operative. One who, until discovered, was very successful at her craft. She pulled the wool over the eyes of the DIA and spied for the Cuban government for many years.

The story is complex, and Popkins’ account somehow maneuvers through the twists and turns.

If you want to experience what I did–if a little less coincidentally–click here to read Popkin’s full article, and meanwhile play this recording I made of the Cuban numbers station HM01, below:

Note that the year Montes listened to the Cuban numbers station on 7,887 kHz, it only contained numbers–unlike the recording here of HM01 (Hybrid Mode 01) which contains both voice and RDFT data bursts (which you can also decode, but not necessarily decipher).

This recording of the Cuban numbers station HM01 was recorded on April 24, 2013, at 10:00 UTC on 5,855 kHz in AM. Click here to download the recording as an MP3.

Again, click here to read Jim Popkin’s full story of Ana Montes on The Washington Post Magazine website.

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Rijmenants’ paper sheds light on Cuban numbers stations

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I’m always amazed by the remarkable talents and extraordinary knowledge of SWLing Post readers. Dirk Rijmenants recently commented on one of our Cuban spy numbers station postings:

[T]hanks for your work on this fascinating blog.

I have additional information on how and who used these Cuban numbers stations. I composed a paper based on FBI and court documents. “Cuban Agent Communications” can by found in the Papers section of my website.

Here’s the direct link (pdf):
https://www.ciphermachinesandcryptology.com/papers/cuban_agent_communications.pdf

Have fun reading!

Dirk Rijmenants
Cipher Machines & Cryptology

I’ve read Dirk’s paper, which does, indeed, shed light on the process of receiving and decoding numbers. Most of all, it exposes the vulnerability and fallacy of using anything other than one-time decryption keys and single-use pads. Why? Most of what the FBI has learned about Cuban numbers came from laptops that were used to help decrypt coded messages–an unnecessary procedure when numbers can simply be decoded on note pads that can then be burnt or destroyed.

But don’t take my word for it–download and read Dirk’s paper “Cuban Agent Communications” by clicking here. Also, be sure to check out Dirk’s blog and cryptology website; I’ve bookmarked both.

Thanks for sharing your findings, Dirk!

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Slate Magazine explores how Russian spies used shortwave radio

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Slate:

It may seem like the digital era of spy technology has passed the Russians by. In the Washington Post, columnist Jeff Stein tittered that “the FBI must have been clapping its collective hands when it discovered the primitive radio techniques the Russians were using.” But they aren’t the only ones using short-wave radio for espionage. Great Britain has publicly admitted that its foreign intelligence agency, MI6, still uses “numbers” stations. And scientists have tracked numbers broadcasts to transmitters at government sites in Israel and (until they went silent in the late ’90s) the United States…

…The reason this dusty method is still ideal for espionage is that, even if you locate a spy station’s transmitter, you have no idea who’s tuning in across the hemisphere. Unlike telephone or Internet connections, receiving a radio signal leaves no fingerprint, no traceable phone connection, no IP address, and no other hint as to where the recipient might be.

Read the full article on Slate Magazine’s website and my previous post about the Russian spies who were recently headline news in the US.

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