This page focusses on some of the cipher machines that
featured as Image
of the Month. The machines,
already decribed in detail on other pages of this
website, are omitted. Each photo is accompanied by a
short description of the machine and web links direct the
reader to further information about the machine. You can
click the images to enlarge them.
All images are
copyrighted and the owners of the images preserve all
rights on their image. No use without explicit permission
of the owner!
Siemens &
Halske T-52 - December 2008
The German
Siemens & Halske T-52 Geheimschreiber was an
online teletype cipher machine for high-level
strategic Luftwaffe (German Airforce) messages in
the Second World War. It was one of the most
secure German cipher machine. The early T-52a and
T-52b versions were less secure. Their traffic
was broken by Swedish cryptologists in 1940 and
these messages were read throughout the war. The
British codebreakers discovered the use of the
T-52 in 1942 and codenamed its message traffic
STURGEON. Although they succeeded in breaking a
small part of STURGEON, they did not achieve the
same success as they had with the Enigma and
Lorenz machines. The T-52 enciphering was by far
the most complex one. However, an important
mistake by the Luftwaffe was that their messages
were often sent through both T-52 and Enigma.
With the Enigma broken on a regular basis, the
T-52 traffic became less important and Bletchley
Park gave priority to the Enigma traffic.
The T-52 was basically a combination of
a Telex machine and a cipher machine. It used ten
pinwheels of different sizes of which the output
states were XORed with each other in a complex
fashion. The output of these logic functions was
mixed with the standard five-bit Telex signal of
the machine through XORing and swapping of the
bits. The early T-52a and T-52b had several
security flaws and were less secure. The T-52c
had a more complex logic mixing of the pinwheel
output and the T-52d incorporated a highly
irregular stepping of the wheels, controlled by
cams. The T-52e was a combination of the
improvements of the T-52c and T-52d, and was a
highly secure machine.
The American
SIGABA was probably the most secure rotor cipher
machine during WW2. The SIGABA ECM Mark II (CSP
888/889) had three banks of five rotors each. One
set of five rotors was used to encrypt the
alphabet. The other two banks of rotors were used
to scramble the signals that control the movement
of the encryption rotors. The result is a very
irregular and complex stepping of the encryption
rotors. The SIGABA was a most secure machine and
its message traffic has never been broken. It
remained in service until the 1950's, when it was
replaced by more modern systems such as the KL-7
and on-line ciphering machines.
During WW2 the US and Britain both
developed a compatible cipher machine system,
based on their own machines. On American side the
special SIGABA CCM (Combined Cipher Machine),
designated ASAM 5 by the Army and CSP-1700 by the
Navy, was equipped with the CSP-1600 Typex
compatible rotor cage. This machine was
interoperable with the CCM version of the British
Typex cipher machine. After the war, the CCM
remained in service between The US, Britain and
Canada, and later on within NATO.
The SIGABA was a wonderful
machine that incorporated the newest developments
in the field of cipher machines. Unfortunately
all machines were systematically withdrawn and
destructed for reasons of security. Only a
hand-full most rare ECM Mark II's survived in
museums and the special SIGABA CCM version is an
even more endangered species. The story of the
Famous German Enigma cipher machine is now widely
known to the public, but regretfully the SIGABA
with its far better cryptographic strength as the
Enigma is only known within the world of
cryptography.
More information is available
on several good websites. On the Pampanito
website you can read all about the history of the
ECM Mk II. They also published the complete
SIGABA manual. More technical details are found
on John Savard's website. Jerry proc provides
more military information on both the SIGABA ECM
Mk II and the CCM version. Finally, you can also
read the Cryptologia article on SIGABA.
The photo shows a
Converter M-209-B, manufactured by L.C.
Smith-Corona Typewriters. In 1940, the US
military selected the Hagelin C-38 as tactical
ciphering device and designated it as M-209. The
US Navy designated it CSP-1500. It was a lunchbox
sized - highly portable - cipher machine with a
simple and compact but ingenious design. By the
end of the Second World War over 140,000 of these
small M-209 machines were produced in the US. The
M-209 is a typical pin-and-lug cipher machine
with six relatively prime sized pin wheels, a
drum with 27 sliding bars and a
letter-dial/print-drum with reciprocal alphabet.
Although the M-209 was not very secure, the easy
to use and small machine was ideal for use in
tactical circumstances where the content of the
messages was no longer of importance after a few
hours.
The ETCRRM
(Electronic Teleprinter Cryptographic
Regenerative Repeater Mixer) from the Norwegian
company STK (Standard Telefon og Kabelfabrik A/S)
applied one-time encryption on a standard
commercial teleprinter. The ETCRRM mixed the
five-bit Telex output signal with a one-time tape
by XOR-ing both signals. An identical setup on
the receiver's end, with an identical key tape
stream, reversed the enciphering process. The
one-time tapes or key tapes were truly random
five-bit values. As long as there are only two
copies of a one-time tape, these tapes are used
only once and they are destroyed after use, the
messages that are sent by this systems are
mathematically unbreakable. The ETCRRM used
tubes, relays and diodes to implement the logic
XOR functions. A solenoid and ratchet system, the
only mechanical parts in the machine, advanced
the key tape.
The ETCRRM
was used for high level military communications
in several countries. ETCRRM's were also used on
the Washington/Moscow Hot-line. Two were
installed in Washington and two in Moscow.
Although a system with absolute security, the
unclassified standard teleprinters and ETCRRM's
were sold by commercial firms and therefore did
not disclose any secret crypto technology to the
Soviets. Only the key tapes were considered
secret crypto material. The Hotline was a full
duplex teleprinter circuit, and not a so called
'Red Phone', as it was believed that spontaneous
verbal communications could lead to
miscommunications and misperceptions.
The KWR-37
"JASON" was the receiver part of the
KW-37 crypto system, developed by the NSA In the
1950's. The systems consisted of a KWT-37
transmitter and a KWR-37 receiver. It was used to
secure fleet broadcasts of the US Navy. The shore
station transmitted 24 hours a day a continuous
stream of encrypted random data. If a message had
to be sent to one of the ships, the encrypted
message was inserted into the continuous stream.
An enemy eavesdropper could not detect if or how
many message were sent, when they started or
ended, or how long they were. Therefore, the
KW-37 system made traffic analysis by the
adversary impossible. The output of the receiver
was connected to a teletype machine that
immediately printed the decrypted stream onto
paper. Transmitter and receiver maintained
synchronisation whole day. If synchronisation was
lost, the receiving operator could re-established
synchro by re-setting and running very fast
through all past key stream until the KWR-37
could pick up the current stream again.
The KWR-37 was a marvel of
miniaturisation in the 1950's. It contained
approximately 500 miniature vacuum tubes for a
large number of flip-flops and logic functions,
required for the shift registers that generated
the pseudo-random enciphering stream. The key of
the KWR-37 was an IBM style punch card that was
changed daily, just before the new synchro at
midnight. The machine remained in service until
the early 1990's.
The Russian
FIALKA M-125 is the most famous Soviet cipher
machine of the Cold War era. In 1965, the
Cyrillic version was introduced in the Soviet
Army, and later on, versions with Czech, Polish
and (East) German keyboard layout entered service
in the Warsaw Pact. The FIALKA was operational
until at least the 1990's and according to some
sources even still in use today. Therefore, the
FIALKA and its specifications were top secret
until the late 1990's. The image shows the
M-125-3MP2 version with Czech keyboard.
Although based on the WW2 German Enigma
machine, Russian cryptologists were well aware of
the security flaws of the Enigma and incorporated
solutions to all of those flaws into this
wonderful piece of mechanics. The small machine,
only 10.8 by 12.5 inches and 8.3 inches high, is
with its impressive mechanism the Swiss watch of
the electro-mechanical cipher machines. The
Fialka has 10 interchangeable, alternately
counter-rotating rotors with 30 wirings each.
Pins on each rotor mechanically control the
irregular and most complex stepping of the
rotors. The disassemblable internal wirings core
of each rotor can be rotated, extracted and
mirrored, or exchanged with other wirings.
Several different types of rotor sets were
produced. The plugboard, as used on the Enigma,
is replaced by a punched card reader, and an
electronic 3-point circuit in the reflector
solves Enigma's flaw that a letter can never be
encrypted into itself. The output is printed on a
paper ribbon or punched on a five-bit paper tape,
and the machine is also equipped with a paper
tape reader.
The TSEC/KL-7,
codenamed ADONIS or POLLUX, is an off-line rotor
cipher machine that was developed in the late
1940's by the American National Security Agency
(NSA) as a successor of the SIGABA. The machine
entered service in 1952. ADONIS and POLLUX were
two different encryption procedures for the KL-7.
The American ADONIS procedure applied an
encrypted message key to preset the initial
startposition of the rotors, whereas the
‘export version’ POLLUX procedure used
far less secure non-encrypted message keys. The
KL-7 was compromised by John Walker who sold
technical information and key lists to the
Soviets. The KL-7 was used by the US and many of
its Allies and retired in 1983.
Output of the KL-7 was printed on a
paper ribbon and some versions had a paper
puncher for 5-bit code output. The KL-7 has eight
rotors (the fourth from the left was stationary)
with 36 contacts each. During its service time,
the rotors were recalled and re-wired regularly.
The rotors are placed in a rotor basket, called
KLK-7 which can be removed from the machine base
KLB-7. Each rotor is placed in a plastic outer
ring with cams. Microswitches, controlled by
these cams, engage electro-magnets which in turn
step the rotors. This resulted in a highly
irregular stepping of the rotors. The 26 inputs
and outputs of the rotor basket are used to
encrypt the letters. The 10 remaining inputs and
outputs are looped back through the rotors,
resulting in a very complex signal path for the
26 letters. The machine was non-reciprocal. This
was achieved by a sliding permutor board
underneath the keyboard which swapped all input
and output contacts of the rotor encryption. The
exact rotor and stepping unit wiring remains
classified. Today, all publicly availably
machines, such as this machine from the Royal
Dutch Signals Museum, are carefully sanitized and
stripped of any wiring, related to the rotors and
stepping unit.
