Numbers in
the Air
Numbers stations are mysterious
shortwave radio stations, broadcasting streams of
numbers or letters using the phonetic alphabet,
by voice, or by Morse. The messages are usually
groups of four or five numbers or letters and are
typically repeated by reading each group twice or
repeating the entire message. These stations are
unlicensed high power HF transmitters,
broadcasting worldwide in various formats and
languages.
They do this day and night on a
wide range of frequencies and it's been going on
for decades, yet no single private, commercial or
government agency ever stepped forward to
officially confirm that they are responsible for
these strange broadcasts. However, today there is
enough evidence that these stations are used by
Intelligence agencies to send encrypted messages
and operational instructions to their agents in
covert operations abroad.
The messages are broadcast on
very powerful shortwave transmitters with
frequencies ranging from 3,000 to 30,000 Khz. The
numbers or letters are spoken in many different
languages, usually a female voice, but sometimes
male or those of children. Many of the broadcasts
are mysterious mechanically or electronically
generated voices. The stations often use
introduction signals as a beacon, prior to a
message. These are repeating phrases, electronic
sounds or music, that enable the receiver to
adjust his radio to the desired frequency.
Radio amateurs monitor these
broadcasts and they sometimes give nicknames to a
station, according to its typical introduction
phrase (e.g. the Cuban "Atencion"
station), prelude music (Swedish rhapsody) or
language of the voice (Bulgarian Betty). Some
stations are called counting stations, because of
their introduction signal. An example is the
Cuban "Atencion 1234567890".
The Cold War era, from the
1950's until the end of the 1980's, is known for
its numerous and very active numbers stations,
not by coincidence the heydays of espionage. Many
of the broadcasts came from the Eastern-block
countries, China and Cuba, but also from several
Western countries.
After the 1989 fall of the
Berlin Wall, the number of stations significantly
decreased from countries like East and
West-Germany, Yugoslavia, Hungary or Bulgaria.
The voices of those stations were mostly Russian
or German. However, several decades after the end
of the Cold War, stations remain active in the
former Soviet-Union, Europe, and in North and
South America, and new stations continue to
appear all over the world.
Most numbers stations use a
basic format to send the streams of numbers or
letters. Some stations broadcast every day at a
fixed hour, and disappear after a few days or
weeks. Other stations have an irregular time
schedules and appear and disappear over time. One
of the most regular numbers stations ever was the
Lincolnshire Poacher (E3 Voice), named after the
English folk song that was used as its interval
signal. After transmitting the very recognizable
melody and a call-sign for about ten minutes, the
message was sent by an electronic
English-accented female voice in groups of five
figures. The station aired every day from the
1970's until 2008. A simple small shortwave radio
was sufficient to capture the Lincolnshire
Poacher. It is believed that the station
broadcast from the RAF Akrotiri basis in Cyprus
and that is was operated by the British Secret
Intelligence Service. Unfortunately, the world of
radio waves lost a true Cold War icon when the
station went off-air in 2008. Its Asian sister
station Cherry Ripe however is still active.
Why Numbers Stations
Although no government or legal
broadcaster ever acknowledged any involvement in
these broadcasts, it is obvious that the costs
and organization of such large-scale illegal
broadcasts can only be supported and approved by
government agencies. Countries like Russia, China
and the United States exploit large shortwave
antenna parks in their own country and at their
embassies abroad.
The content and structure of
the messages are identical to cryptographically
encrypted messages. The groups appear to be
totally random and without any logical order or
meaning. It is assumed, and confirmed in several
uncovered spy cases, that the seemingly random
numbers or letters are actually one-time-pad
encrypted messages. During the Second World War,
special espionage and sabotage teams, operating
behind enemy lines, received their operational
instruction through one-way broadcasts of
one-time pad encrypted messages.
History has proven this to be a
most secure method. One-time pads are sheets or
booklets with keys that consist of series of
truly random numbers or letters. Enciphering and
deciphering a message only requires pencil and
paper and some basic calculations. Each message
is enciphered with a unique one-time pad which is
destroyed after one-time use. If properly
applied, one-time pad is the only system that is
proven to be mathematically unbreakable. For more
information, visit my one-time pad page.
The one-way shortwave broadcast
has many advantages for Intelligence agencies.
Powerful shortwave transmitters reflect their
signal many times between the earth's surface and
the ionosphere, carrying them over very long
distances. This enables Intelligence agencies to
send messages to agents located in far away
countries. The many reflections also make it
difficult to accurately locate the transmitter
and find out who is broadcasting. The enormous,
almost global range of shortwave makes it
impossible to identify the country of
destination, let alone the person who receives
the message.
Therefore, there is little risk
of exposing the secret agent who receives a
message. A simple commercial shortwave
world-receiver can pick up a messages and the
agent doesn't need a compromising special
receiver or crypto equipment. He can easily carry
and hide a large number of one-time pads in small
booklets or on microfilm, and the manual one-time
pad system, although slow and elaborate, requires
nothing more than a pencil and paper. Therefore,
numbers stations are an ideal method of covert
one-way communication to illegal agents abroad.
Evidence for use as Spy
Stations
Over time, declassified
documents from court trials and Intelligence
agencies revealed the truth about these
mysterious numbers stations. They also show that
the era of spy stations and espionage is far from
over. This information enables us to discard all
stories about numbers stations being so-called
weather buoys, shipping reports or other decoy
fairytales. Several spies have been caught in
possession of shortwave radios and one time pads.
Given the widespread and frequent use of numbers
stations, the published cases are undoubtedly
only the tip of the iceberg.
In 1962, Soviet GRU Colonel
Oleg Penkovsky was arrested by the KGB and
charged with espionage. During a search of his
Moscow apartment, KGB found one-time pads,
instructions on how to receive and decipher
encrypted radio messages, a Sony shortwave radio,
a Minox camera and other spy equipment, cleverly
hidden inside a secret compartment in his desk.
More info, Andrei Sinelnikov
[Rus] [Eng].
Documents of the East German
Ministerium fur Staatssicherheit (Stasi),
describe in detail intercepted packets, destined
for German CIA agents that lived in the former
DDR, with one-time pads, instructions on how to
receive numbers messages on shortwave radio and
the deciphering procedures for these messages.
These are published on the SAS und
Chiffrierdienst
website.
Michael Michnowski defected
together with Stasi agent Werner Stiller from
East Germany in 1979. He published his story
about the preparations and the defection. In that
story he describes the covert
communications with the
Bundesnachrichtendienst (BND), West-German
intelligence, and how they used a shortwave radio
to receive one-time pad encrypted instructions,
sent by BND numbers stations. You can watch a video of a speech and Morse generator used by
the East-German Stasi, or listen to the voice output (mp3). This is the machine behind the
infamous East-German lady. The machine was
stangely enough labeled in English, but this was
because it was exported to many other
Eastern-block countries.
In 1988 Vaclav Jelinek, a Czech StB spy who operated under the
false identity of Erwin van Haarlem, was arrested
by British Special Branch detectives while
receiving a numbers message on a shortwave radio
in his London apartment. One-time pads were found
on microfilm, hidden in bars of soap. The pads
enabled the detectives to decipher some of the
received messages, which were later used in
court. Jelinek was sentenced to ten years of
imprisonment.
More recently, there were
several spy cases in the United States, related
to Cuban numbers stations . In the 1998, the
so-called Cuban Five from the Wasp Network spy ring, agents
of the Cuban DGI (Dirección General de
Inteligencia), received instructions by
encrypted messages that were sent each day by the
Cuban HF numbers station "Atencion".
Another one was the Ana Belen Montes case, a senior US Defense Intelligence
Agency analyst, spying for Cuba. She was arrested
in 2001 and the federal prosecutors stated:
"Montes communicated with the Cuban
Intelligence Service through encrypted messages
and received her instructions through encrypted
shortwave transmissions from Cuba". More on
the Belen Montes case in this FBI affidavit
(pdf).
In 2006, Florida International
University professor Carlos Alvarez and his wife Elsa Alvarez were charged
with espionage and acting as agents for Cuba. The
US District Court Florida stated:
"Defendants would receive assignments via
shortwave radio transmissions. These messages
were encoded in five-digit groupings. Once
received, Defendants would input these coded
messages into their home computer, which was
equipped with decryption technology contained on
a diskette" More in the Alvarez sentencing.
US State Department official Walter Kendall
Myers and his wife
Gwendolyn Steingraber Myers were arrested in 2009
on charges of serving as illegal agents of the
Cuban government for nearly 30 years. They
acknowledged having received encrypted messages
from the Cuban Intelligence via a shortwave radio
they possessed. The Columbia State District Court
indictment stated that "Cuban intelligence
broadcasts encrypted shortwave radio messages in
Morse Code or by a voice reading numbers"
and also that "It was part of the conspiracy
that Cuban Intelligence would and did broadcast
shortwave messages in Morse code which were
receive by Kendall Myers". More about this
case in the Myers court
indictment. More
information about Cuban numbers stations and
agent communications procedures in the Cuban Agent Communications (pdf) Paper.
Note: all espionage radio
equipment images on this page are copyrighted by
Detlev Vreisleben. More about him on License To Shoot.
|
Specially designed
interference-radiation free shortwave
agent receiver type 32310.
© Detlev Vreisleben
|
A 1950's SW to MW converter to
receive messages from BND (West-German
Intelligence) on a normal MW radio. In
those days, commercial SW radios were not
available in East-Germany. Unfortunately,
the converter was notorious for its
unwanted and strong interference
radiation. © Detlev Vreisleben
|
A standard commercial shortwave
receiver, ideal to covertly receive
numbers messages. If discovered, this
radio will not arouse any suspicion.
|
A seemingly innocent AA type
battery, cleverly crafted to contain
clandestine items such as one-time pads
or microfilm. This item was used by a
foreign intelligence service.
© Canadian Security Intelligence Service
|
CIA one-time pad, used by
Alexander Ogorodnikov.
Source: KGB Archives
|
(click
the images to enlarge)
|
From
Cold War to Cold Peace
Are numbers stations still
useful in this age of global communications,
Internet and satellite links? Yes! The so-called
end of the Cold War did not bring a significant
decrease in espionage activities. In the
contrary, the Cold War is merely replaced by a
Cold Peace where espionage is booming. In today's
world, with the globalization of economics,
politics and conflicts without borders, covert
and illegal agents of Eastern, Western, Asian and
Far East countries still operate extensively in
each others countries to gather Intelligence and
execute operations. They still need a secure way
to receive their operational instructions and
messages. However, today, all modern
communication systems are controlled by computers
and therefore insecure.
Telephone, Internet and even
satellite transmissions can be monitored. E-mails
can be intercepted and read. Some government
agencies have the money and resources to monitor
communications and trace both sender and
receiver. An example is the huge ECHELON project
which globally intercepts and identifies all
kinds of communications. In times of conflict,
countries can simply block the Internet or other
communications, or even simply switch off
satellites. There have been successful tests to
destroy satellites with missiles, making
satellite communications unreliable during a
serious conflict. Or did you really believe to
continue using telephone or Internet between,
let's say, Russia and the United States, if they
where at war with each other?
Imagine a war broke out and
intelligence personnel are operating behind enemy
lines. The only secure and reliable way to
communicate with them would be the good
old-fashion long distance shortwave radio. But
even in times of peace, some covert operations
are so sensitive that discovering them would
bring governments big problems or embarrassment.
It is believed that some numbers stations
continuously send fake messages, just to keep the
lines open, ready for use. Those who monitor
these stations are unable to notice when a
station suddenly changes from sending random
numbers to operational encrypted traffic. A good
example is the Lincolnshire Poacher, sending
messages of 200 groups each, every day, for
almost 40 years. Reasons enough why numbers
stations are still active and useful. With their
long and outstanding career of more than 70
years, the numbers stations have become an icon
of espionage.
And still, every single day,
numbers messages are transmitted all over the
world, spoken in English, Russian, Spanish,
Chinese and many other languages. Who's
broadcasting them and, even more intriguing,
who's listening to them...?
Some recordings
 |
Lincolnshire Poacher (863 Kb) English female voice,
MI6, introduced by a melody |
|
Swedish Rhapsody Child (188 Kb) This is a mechanical
child voice, introduced by an 'ice cream
man' melody |
|
Attencion Station (250 Kb) The well known Cuban
Attencion station, broadcasts for Cuban
agents in the U.S. |
|
Yankee Bravo (131 Kb) German female voice,
probably of KGB origin, introduced by the
call sign YB |
|
Russian Male (83 Kb) Russian male voice, KGB |
|
East-German 'Stimme' Voice output of the East-German
'Stimme' Generator (365 Kb) |
Right-click the icon and
select 'save target as' to download the mp3 file.
Numbers on the Internet
Numbers messages can also be
distributed through the Internet. The Numbers
Relay Page (NRP) is an online method to post
numbers messages. The NRP is an easy way to
exchange encrypted messages without disclosing
the sender or receiver and requires only a
computer with Internet browser.
More about the NRP on this
page.
More on this website
Off-site Links
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Paper on Cuban
numbers stations, Cuban agents in the
U.S. and the errors they made 
2013 movie with John Cusack
and Malin Akerman about a CIA numbers
station