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Ministerium für Staatssicherheit · MfS
Ministerium für Staatssicherheit, commonly abbreviated MfS
or Stasi,
was the Ministry for State Security of the former DDR (East-Germany). It was
one of the most effective and repressive secret
intelligence and police organisations
to have ever existed, with strong links to the
Soviet KGB
[1].
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The origin of the MfS/Stasi dates back to the establishment of the Deutsche
Demokratische Republik (DDR) — the German Democratic Republic (GDR) —
on 7 October 1947, shortly after the end of WWII, in the Soviet-occupied part
of Germany. At that time, the agency was known as Hauptverwaltung zum Schutz
des Volkseigentums (Main Directorate for the Protection of Public Property).
On 8 February 1950 it was renamed Ministerium für Staatssicherheit
(Ministry for State Security), abbreviated: MfS or Stasi.
Between 1953 and 1955, the Stasi operated under the control of the
Innenministerium (Internal Affairs).
During the existence of the DDR, the Stasi had files on nearly everyone in
the country, but also on a number of people and dissidents abroad.
After the fall of the DDR in 1989 and the subsequent
reunification of Germany in 1990,
it became clear that a number of security services and people had tried to
destroy Stasi files. Nevertheless, about 11 km of files have survived and are
now publicly available through the BStU.
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It is estimated that at the time of the collapse of the DDR (1989),
the Stasi had 91,000 employees and 200,000 informants, the so-called
Inoffizielle Mitarbeiter (IM). That is one per 50 citizens,
probably the highest penetration by a security service ever [1].
The MfS was renamed Amt für nationale Sicherheit
(AfNS) at the end of 1989, and was dismantled during the course of 1990.
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Stasi equipment on this website
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Stasi projects and operations on this website
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During the existence of the Stasi, its Hauptverwaltung Aufklärung
(HVA) — Main Directorate for Reconnaissance — was responsible for domestic
and foreign information gathering (espionage),
and for conducting covert operations in foreign countries. For most of the
time (1953-1986), the HVA was headed by the mysterious Markus Wolf [2].
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Like most intelligence agencies, the Stasi gathered information and
carried out covert operations in other countries, in particular in Western
Europe. The espionage intensified after, in 1973, the DDR was officially
recognised as a country by the United Nations. This enabled them to establish
embassies in all major Western countries, and provide a legal (diplomatic) cover
for its spies [5].
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Technical surveillance and countermeasures
TSCM
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For observation of people and organisations, the Stasi had a wide range of
technical facilities to their exposal, some of which were developed or
adapted in-house. The various fields were described as assignments,
each of which was identified by a letter, as shown in the table below:
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B - Acoustic surveillance
covert listening devices
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During the Cold War, citizens of the DDR (East Germany) were under constant
surveillance of the Stasi, especially if they had political motives.
After the fall of the Berlin Wall in 1989, it became
clear they had 91,000 full-time employees and more than 200,000 informers.
That is one per 50 citizens.
Some sources even claim that the Stasi had one informer per 6.5 people [1].
At one time or another, nearly everyone had been asked to spy on their neighbours
or their family members.
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The Stasi was particularly interested in people who objected Communism
and people with a public opinion, such as journalists and artists.
Over the years, many of them were subjected to surveillance
for several weeks, months or even years. People were tailed,
covertly photographed,
their phones were tapped and
listening devices (bugs)
were sometimes planted in their homes.
The image on the right shows a sophisticated listening device –
made in the late 1970s by a Bulgarian company – that was used by the Stasi.
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It was one of many different devices and techniques that were used to
monitor people in their homes, at their workplace or in public areas. In many
cases the existing infrastructure – such as telephone lines and Cable TV
wiring – was used to make eavesdropping easier and more efficient.
In a bugging operation, the room or person under surveillance is commonly
known as the Object, or the Target.
For bugging an object, the Stasi had the following techniques at their disposal:
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In addition, the Stasi had access to a wide range of other techniques for
surveillance operations, such as telephone tapping, visual observation,
radio interception,
video surveillance,
covert recording,
covert photography,
surreptitious entry,
manipulation, compromise and infiltration.
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When placing a bug, the most difficult job for the Stasi was to determine
in which room the most interesting conversations were held, as it was
practically impossible to bug each and every room in the house. Once the
ideal location was established, they had to covertly place the bug.
Doing
this in an inhabited house whilst the residents are out, is very dangerous,
as there is always a chance that they return unexpected, or that they notice
that something has changed. For this reason, the bugs were often brought in
by drilling a hole in the wall from the neighbour's.
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The image above shows how this was done. When the residents were out,
a hole was drilled through the wall from the neigbour's living room,
until just behind the plaster or wallpaper.
A good place to drill with little change of discovery,
was behind a power socket, as there
was likely to be a similar socket at the other side. In most cases, a
non-metallic tube,
or probe,
was placed in the hole, guiding the sound from the other side
to the microphone in the neighbour's house.
For financial reasons, bugs were always in short supply in the DDR, which
is why they had to be retrieved after a bugging operation had ended.
This was particularly the case for carrier bugs (TF) and radio bugs (HF),
but less so for wired bugs (NF) in prisons and (international) hotels,
as these were often under continuous surveillance.
The various types of bugs are further explained below.
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The diagram below gives an overview of the various techniques that were
used by the Stasi for wired bugging operations. This category consists of
two groups: carrier bugs,
which use existing infrastructure, and audio bugs,
for which dedicated wiring is used. For all systems, dedicated interfaces
were available for transporting the signals via other (generally long-distance)
media.
At the left are the various wired bugs, identified by their project number.
For each type of line there is a matching interface that can be used to
retrieve the audio signal at the end of the line. From there, the signal is
either fed to a local monitoring station (e.g. a listening post), or to
a central Stasi control facility, commonly referred to as
Centrales Kontrollsystem (CEKO) [4].
➤ Original Stasi diagram of NF and TF B-technology [A]
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The diagram below gives an overview of the complexity of a wireless Stasi
bugging system, in its many configurations. At the left is the target area
in which a miniature transmitter is hidden, here shown as the B-TX. It is
a low-power transmitter which can be picked up at a terminal station
in the vicinity (typically 50-150 metres away). In order to save power and
to reduce the chance of discovery and exposure, some bugs were equipped with
a so-called switch receiver, here shown as S-RX. It allows the
transmitter to be remote controlled from the nearby terminal station.
For simple short-term operations, the terminal was used as the
listening post. It had facilities for remote controlling the bug and
for recording and monitoring the signal received from it. For more important
or long-term operations, the terminal was commonly linked to the
central command system (CEKO), either directly or via an
intermediate station that acted as a relay.
The terminal was connected to the central CEKO system – or to the
intermediate station – either wirelessly (via a bi-directional radio
link) or via dedicated telephone lines, in which case audio (NF) or
carrier (TF) technology was used. These
links carried both audio and control signals. For medium-profile operations
it was also possible to use the intermediate station as the endpoint.
If the distance between the target area and the terminal was too
large, the B-RX receiver could be enhanced with a pre-amplifier that
was placed (with the antenna) closer to the target. In the same vein,
a mobile switch transmitter (S-TX) was available in order to get closer to
the switch receiver when activating the bug. In most cases it was placed
in a car that drove past the target area.
➤ Original Stasi diagram of HF B-technology [B]
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The first category (NF) was used in places where dedicated cabling for
the bug could be installed, which could take hours or even days.
Such bugs generally consist of a small microphone — often made by companies
in the West such as Sennheiser
and Knowles — and a miniature amplifier.
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The bug was connected to the dedicated cable, and its signal could be monitored
and recorded several hundred metres away at the end of that cable. In some
cases, the monitoring point was patched to a central Stasi listening post via
other infrastructure, such as a leased telephone line.
When correctly installed and hidden, wired audio bugs can be extremely difficult
to find. They can be embedded in a wall, with the sound port of the microphone
requiring a tiny hole of no more than 1 mm. A good example of a such a bug
is the Bremen 20
shown in the image on the right.
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The red and blue wires at the right are connected to the dedicated cable and the thicker
grey wire leads to the microphone which was commonly hidden inside
a plastered wall. If the sound port of the microphone was extended with a hollow
pipe made of plastic or wood, the device could be embedded deeper inside the
plastered wall, making it virtually 'invisible' to metal detectors.
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Apart from the audio bugs discussed above, the Stasi could also use the existing
infrastructure of a house, an apartment building, an office, a district or even a city.
The bug was then installed as a parasitic device on an existing cable,
using that cable to power the device and deliver its content.
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Examples of existing infrastructure are the telephone line, the mains power cables,
an intercom system in an apartment building, a common door-opener or a central
antenna installation.
Such cables are usually available in every house and in some cases even in every
room. As they are primarily used for the transport of other signals,
the audio from a covertly installed bug had to be hidden, or masked,
in such a way that it could not be picked up accidentally. This was done by modulating
the audio onto a so-called carrier wave above the audible frequency range.
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Once modulated, the signal was injected into the cable and picked up at a
tapping point several hundred metres away, where it was demodulated, recorded and
eventually transcribed. A good example of a carrier wave bug is the Bulgarian bug
Bodil, which is shown in the image above.
Bodil used the existing telephone line for the transport of its intelligence.
Shown here without its protective cover, it could be installed nearly everywhere,
for example inside a piece of furniture, inside a wooden wall or inside the
telephone connection box. The audio could be retrieved with a special receiver
which was placed elsewhere in the building or in some cases even outside the target
area. For long-term surveillance it was even possible to patch the signal directly
to a Stasi listening post by using an additional free dedicated telephone line.
Similar technologies were available to bug a room via an intercom line or
via the 220V power lines of the mains AC network.
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In the rare event that the existing infrastructure could not be used for bugging
a room, the Stasi used radio bugs, also known as High Frequency (HF) or
Radio Frequency (RF) bugs. As they do not depend on existing cables, they can
be installed nearly everywhere, even inside a movable object.
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Radio bugs can be powered from the mains, but in many cases batteries were used,
which greatly reduced their life span. Once the batteries ran out, they had to
be swapped, for which access to the object was required. A risky undertaking.
For this reason, remote controlled bugs were sometimes used. When the bug was
not needed, it could be turned off remotely by the operator at the listening
station, saving precious battery power.
This was useful, for example, during the night when people were
sleeping, when nobody was at home, or when an office was closed.
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Despite popular believe however, HF bugs were only used in a
minority of bugging operations, as their range was very limited and they
could easily be discovered by means of a special detector. In some cases they
could even be discovered accidentally by someone using the radio to tune into
a broadcast station. In other cases, the sound from the bug was hidden from an
(un)intentional eavesdropper by using an
audio-masking technique such as
subcarrier frequency modulation.
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Apart from placing
covert listening devices (bugs)
with their adversaries, the task of the Stasi
was also to check – or sweep – important objects,
such as government offices, hotels and embassies, in order to
discover bugs and other espionage activities from their adversaries,
both foreign and domestic.
This assignment was known as Aufgabe X (assignment X) and the technology for
it was commonly known as Kontertechnik (countermeasures),
or Operatieve Kontroll- und Suchtechnik (operational check and search
technology), or more generally as: X-Technik (X-technology).
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Known Stasi optical communication systems
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Although some devices have a codename, all technology that was used by
the Stasi, was given a project number. This was also the case for equipment
that was bought from security services in other countries, such as Bulgaria,
although in some cases the project number is unknown.
The diagram above shows how the project number is constructed.
The first digit tells us which department was responsible for it. In this
case it is department 33, which was Außenstelle Beucha (Outstation
Beucha). Before 1977, the prefix '3' was omitted, or the prefix 'AB' was used.
The next two digits define the theme and the group within
the theme. The next two digits define the actual project (within the group).
If a device is part of a kit, the number behind the dash specifies the item
number (within the kit). The last two digits are optional, and
specify the version or variant.
➤ Overview of Stasi project numbers (off-site)
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Audio sensitivity classes
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Depending on the type of microphone that was used with (or inside) a bug,
and the number of amplifier stages in the circuit, some devices had a
better audio sensitivity than others, allowing the speaker to be further
away from the microphone. For this reason, the audio sensitivity of a
bug was often specified as one of the following classes (measured at
75 kHz deviation):
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- 0.5 ± 0.3 µbar — low sensitivity
- 1.1 ± 0.3 µbar — medium sensitivity
- 1.7 ± 0.3 µbar — high sensitivity
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BStU
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Bundesbeauftragte fur die Stasi-Unterlagen
Officially: Bundesbeauftragte für die Unterlagen des Staatssicherheitsdienstes
der ehemaligen Deutschen Demokratischen Republik
(DDR) —
Federal Commissioner for the Records of the
State Security Service of the former German Democratic Republic
(GDR).
➤ Website
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CEKO
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Centrales Kontrollsystem
Contral Control System — Electronic system, developed by the Stasi in the
mid-1960s — for processing telephone taps and wired covert liestening
devices (bugs). The system was succeeded by CEKO 2.
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ESG
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Endstellengestell
German word for terminating unit or end-of-line device.
In this context used for the final (remote) listening post or monitoring
station.
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HF
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Hochfrequenz
German word for High Frequency (HF), also known as Radio Frequency (RF).
In this context used to identify radio bugs.
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HVA
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Hauptverwaltung Aufklärung
Main Directorate for Reconnaissance, a department of the Stasi,
responsible for foreign and domestic espionage and for foreign
covert operations.
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IM
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Inoffizielle Mitarbeiter
Unofficial Employee — Stasi name for civil informants, inside and outside
the DDR, often recruted by means of compromise and manipulation.
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IR
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Infrarot
German word for Infra-Red (IR). Light rays at the red end of the
spectrum, invisible to the human eye.
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MfS
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Ministerium für Staatssicherheit
Ministery for State Security of the former DDR (East Germany);
one of most effective and repressive intelligence and secret police
agencies in the world.
The agency is commonly known as Stasi, which is the abbreviation of
Staats-Sicherheit, and had its headquarters in East-Berlin.
The Stasi had strong ties with the Russian intelligence service
KGB.
➤ Wikipedia
➤ Wikipedia Germany
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NF
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Niederfrequenz
German word for Audio Frequency (AF), also known as Low Frequency (LF).
In this context used to identify audio bugs.
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PE
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Passive Element
Common expression for a covert listening device (bug) that does not need
its own local power source. It is commonly powered by energy that is beamed
at it from a nearby location.
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Stasi
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 Ministerium für Staatssicherheit
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TF
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Trägerfrequenz
German word for Carrier Frequency (CF), commonly abbreviated to Carrier.
In this context used to identify carrier bugs.
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Document obtained from BStU [4] and kindly supplied
by Detlev Vreisleben [3].
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Full name: Bundesbeauftragte für die Unterlagen des Staatssicherheitsdienstes
der ehemaligen Deutschen Demokratischen Republik
(DDR) —
Federal Commissioner for the Records of the
State Security Service
of the former German Democratic Republic (GDR) —
officially abbreviated to BStU.
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© Crypto Museum. Last changed: Friday, 03 February 2023 - 15:55 CET.
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