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Pin-wheel Germany HELL CX-52 →
Nevertheless, HELL managed to improve several aspects of the Hagelin design,
making it more reliable and easier to operate.
As the machine was built
for the army, it is slightly more robust than the
original CX-52
design. In addition, the storage case houses 6 extra cipher wheels, the
maintenance tools and
a selection of spare parts.
The machine is housed in a aluminum case with a metal dust cover. All metal
parts are painted in the Bundeswehr olive-green colour.
The image on the right shows a typical H-54 with its dust cover open
and the transport handle folded out.
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The machine was exclusively made for the German market. The various notes
and checklists are in the German language and so are the settings for
ciphering and deciphering 2 (V/E rather than C/D).
In order to accomodate the spares and maintenance tools, HELL improved
the metal storage case and added a well thought out
storage compartment in the top section of the dust cover.
The paper supply reel is located in a third compartment, at the
bottom of the machine. After removing the
retaining clip at the center of the bottom,
the paper compartment can be opened.
The paper tape is fed through a guide
into the bottom of the printer.
On the top side, the paper is fed behind the printhead, through
the paper feed rollers. A rotating knife
above the paper feed, cuts the paper tape into two individual strips:
one for the plaintext and one for the ciphertext.
For a detailed description of the operating principle of the machine,
refer to the Hagelin CX-52 page.
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CD-57bk was the internal designator given to the machine by licence holder
Crypto AG (Hagelin). It was a
secret designator
that was used by Hagelin
and the NSA to identify the various variants
of the machines.
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V/E = Verschlüsseln / Entschlüsseln —
C/D = Cipher / Decipher
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Immediately after WWII, the Allied Forces implied certain restrictions
on Germany. As a result, the Germans were not allowed to develop critical
technology, such as cipher machines. As the new German Army,
the Bundeswehr, needed cipher machines, HELL was asked to
build them under license from Crypto AG (Hagelin)
in Switzerland.
As part of a secret arrangement
with the NSA,
Hagelin had developed three variants of each machine: a very secure one,
a less secure one and an insecure one. The HELL H-54 is based on the
CD-57b, a less secure variant of the CD-57a.
Like the Hagelin CX-52,
the HELL-54 is a so-called pin-and-lug machine that
uses 6 cipher (pin) wheels as part of its cryptographic engine. Each wheel
has a different number of steps (and hence pins) to complete a full
revolution, all of which are co-primes in order to obtain the maximum
possible cryptographic period. Each wheel carries a number that corresponds
to the number of steps. Unlike the CX-52,
for which 12 different cipher wheels
were available, the H-54 came with a selection of
just six of these wheels, with the following number of steps:
29 31 37 41 43 47
Each of the six wheels is mounted on a metal base plate with a cog-wheel
and the corresponding number engraved. The wheels should only be mounted
on the matching base plates. The base plates can be removed from the
machine by pulling out the
main axle from the right. They can then be
inserted again in 120 different orders (6 x 5 x 4).
The toolbox of the machine contains
six spare pin wheels with the same
number of steps as listed above. This allowed a new set of pin wheels to
be prepaired for next day's cryptographic key well in advance. When the
key was changed at midnight, there would be a minimum down-time.
The machine was interoperable with the
Hagelin CX-52, but only if the
six cipher wheels listed above were used.
The handheld HELL STG-61 was supplied with the
same set of wheels.
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Differences with the CX-52
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The H-54 was built under license from the
Hagelin Company (Crypto AG) in Zug (Switzerland)
and is functionally identical to the
Hagelin CX-52b. Nevertheless, it
has some practical improvements over the CX-52b 1 design.
The most important ones are listed here:
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- Advance lever
The transport handle at the right is more robust
and is in a different position.
Furthermore, it makes full revolutions (like a crank),
whereas the handle of the CX-52 only makes an up/down movement.
The handle can be rotated backwards freely without affecting the
mechanism. The (black) knob of the handle can be folded 'inside' the
handle, but only when the handle it locked in its storage position.
- Hüttenhain feature
Above the cipher wheels is a narrow window with a ruler
(marked 1 to 8). Behind this window is a movable tab that can be clicked into any of
the 8 positions. This feature was added to the design by Dr. Erich Hüttenhain 2
in order to make the machine more secure. It is denoted by the suffix 'k' to
the secret designator: CD-57bk.
➤ More
- Robust enclosure
The outer body of the cipher machine and the
top lid that covers the wheels,
are made of slightly thicker aluminium, making the machine more robust
in day-to-day military use.
- Tools compartment
The storage case is improved over the original Hagelin design. It has
an extra storage compartment in the top section of the lid
for spares and accessories, whilst in the original design, a limited set of tools was
stored inside the top lid itself.
- Removable alphabet ring
The alphabet ring at the front left
can easily be swapped for an alternatively
ordered alphabet by removing the plastic ring. The ring is held in place by
means of a small piece of feathering steel at the left.
On the original CX-52, the letter ring consists of separate letter-inserts
that had to be installed/swapped individually.
- Print wheel retaining clip
By pulling out the print wheel knob at the left side
of the machine, the offset between the two print heads (i.e. the displacement between
the input and the output alphabet) can be adjusted. To prevent this from happening
accidentally, the knob of the H-54 has been given a plastic rig that is
blocked by a retaining lever mounted below it. In order to adjust the
alphabet offset, the lever should be pushed down before pulling-out the
knob.
- Removable dust cover
When using the H-54 with the B-62 keyboard, the dust cover
(i.e. the toolbox) has to be removed from the machine. On the original
CX-52 this was done by unscrewing the rear hinge of the cover. On the
H-54 however, a slide-on cover has been used.
It is held in place by a simple retaining clip at the rear of the machine.
- Simplified case lock
The original CX-52 was issued with either a cylinder lock or a secure
cross lock at the right side. The case could only be opened with the
appropriate key, whilst the cover over the wheels was locked with an
even more secret key.
On the H-54 only simple locks are used, as the
machine was considered to be issued only to qualified personnel. The
lock at the right has been replaced by a simple one that can be operated
with a screwdriver.
- F-V feature always active
Some CX-52 machines are equipped with a so-called Fixed-Variable (F-V) feature
that allows the two print heads to be given an offset with respect to each other.
One some machines this feature can be controlled externally, whilst on others it
can only be enabled and disabled internally. On the H-54, this feature is present,
but is always enabled.
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Like the CX-52,
the H-54 has a revolving cage with 32 horizontally movable
slide bars. Bars 1 to 31 are of type 14, whilst bar 32 is of type 15 as shown
in the table below. This is consistent with the
CX-52b configuration [2].
The various types of slide bars and their effect on the cipher wheels and the
encryption, were described in detail
by Bart Wessel in February 2021 [3].
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Pos
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Shape
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ID
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32
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15
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1-31
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14
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When operating the H-54 (CX-52b), all pinwheels step together by a number of
steps that is equal to the number of pinwheels that is NOT engaged. This is equal
to the complement of the number of bars that is engaged (NBE). This can be written
as follows:
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Number of steps = number of wheels NOT engaged
= 32 - number of bars engaged
= 32 - NBE
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The displacement of the print head (typewheel) is controlled directly by the
number of engaged slide bars in the revolving cage (NBE).
Depending on whether the Hüttenhain Feature (K-feature) is active or not,
the displacement of the print head is defined as follows:
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(K is not active) displacement = NBE
(K is active) displacement = 32 - NBE
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Hüttenhain feature
K-feature
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The HELL H-54 is equipped with the Hüttenhain Feature, developed by
Erich Hüttenhain
of the German post-war intelligence service
OG (later: BND). Internally known
as the Complementary Feature, it was identified with the letter 'K'
after the German word Komplementär. Between the NSA and
Boris Hagelin, the
machine was known by the secret designator CX-52bk.
➤ More
The K-feature consists of a horizontal ruler with a movable slider,
that is positioned above the cipher wheels,
just in front of the locking bar. When the machine is closed, the
ruler is visible through a horizontal slot in the cover,
as shown in the diagram above. The movable slider has eight possible settings,
numbered 1 - 8. In the diagram above it is shown in position 4.
The setting of the slider controls the operation of the K-feature
in the following manner:
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- Always enabled
- Active when the sensed pin of wheel 1 is 'active'
- Active when the sensed pin of wheel 2 is 'active'
- Active when the sensed pin of wheel 3 is 'active'
- Active when the sensed pin of wheel 4 is 'active'
- Active when the sensed pin of wheel 5 is 'active'
- Active when the sensed pin of wheel 6 is 'active'
- Disabled
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The feature is similar in operation to the Inversion Function
of the SG-41 (Hitler Mühle) — a pin-wheel cipher machine that
was introduced by the German Army at the end of the war — and was invented by
Regierungsoberinspektor Fritz Menzer as a replacement candidate
for the Enigma-G cipher machine.
It was described in detail in February 2021 by Klaus Kopacz and Paul Reuvers [4].
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One of the nicest improvements of the H-54 over the original
Hagelin CX-52 is the addition of
a clever storage compartment in the top section of the dust cover.
An extra lock, just above the leather carrying strap gives access to this
compartment. Press the knob to open the top lid.
If it doesn't open, you may have to disengage the
safety lock inside the dust cover first.
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The image on the right shows the H-54 cipher machine with its dust cover
closed and its toolbox open. Some parts are stored on top of the machine,
whilst the remaining parts are stored inside the case lid. A checklist
(in the German language) inside the top lid shows which parts and
accessories should be present.
The lower part contains a spare paper reel at the center. To its left
are two cylinders:
one with spare ink rollers and another one with spare
pins (missing here). At the far left are
6 spare fuses (300 mA and 2A)
for the B-62 keyboard.
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At the front left is a spare print wheel (missing from our set) and at the
far right is a pin-wheel resetting tool (missing here). Behind the front
edge is a spare transparent plastic alphabet ring.
Inside the top lid are six spare pin-wheels,
a pair of tweezers, a pin setting tool,
a brush and a piece of cloth. The pin-wheels are held in place
by a hinged panel that can swing to the left.
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Like the Hagelin CX-52, the HELL H-54 could be enhanced with a large
motor-driven keyboard, which effectively converts the mechanical cipher
machine into a fully automatic electro-mechanical one. For this, HELL
built the B-62 keyboard extension,
which was a copy of the Hagelin B-62, albeit in Bundeswehr green colour.
It is fully interoperable with a Hagelin B-62, which in turn was the
fully transistorized successor to the earlier Hagelin B-52 keyboard.
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The B-62 consists of a large base
in which the motor and the various electronic and mechanical parts are housed.
At the right are the power switch, the fuses and the connection
to the AC mains (110 or 220V) or an external 24V DC source.
The mains cable is fitted permanently.
At the front right is a 26-button keyboard with the letters A-Z
in the German arrangment (QWERTZ). All keys are dark brown
except for the top left one which is red. At the right end of the middle
row is a blind key that is not functional. It is a spare one that is
bolted to the top panel.
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Behind the keyboard is a horizontal bay in which the H-54 machine can be
installed. It should be fitted in such a way that the meachanical drives
at the left line up with the axles that stick out at
the left side of the H-54.
This way the transport mechanism of the H-54 can be driven, as well
as the letter wheel (at the front left of the machine). A small metal lever
can be used to toggle between ciphering and deciphering (in German:
(V) Verschlüsseln and (E) Entschlüsseln).
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At the front left is a large 'blob' with a
hinged panel that swings open
upwards. Behind the panel are four rows of 13 banana-type sockets. The
26 sockets in the outer two rows are red and are marked with the letters
of the alphabet (A-Z), whilst the 26 sockets of inner rows are black.
The black sockets are also marked with the full alphabet (A-Z). 26 patch
cables are used to connect the red sockets to the black ones.
The patch board added an extra layer of permutations to the cipher
algorithm and is the equivalent of a transposed alphabet ring.
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The area behind the plugboard, houses most of the
electro-mechanical parts of the B-62.
It can be accessed by removing the cover from the left side.
The bottom side of the unit contains
the transformer, the motor, the keyboard and the
electronic circuits. The latter consists
of two PCBs with one of the first generations of transistors on them
(AC153). Considering the time it was built (between 1962 and 1965)
the quality of the printed circuit board (PCB) is extremely high.
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Jim Meyer recalls...
During his time in the German Bundeswehr, Jim Meyer was assigned
to the German Army Signals Corps, where he was trained on the
HELL H-54 early in 1962 [1]. Because of the way the transport
arm of the H-54 works, the machine received the nickname
Kaffee-Mühle (coffee-grinder).
Later that year his unit was asked to test the
new B-62 keyboards under a variety of conditions.
For the test, soldiers with full NATO sucurity clearence had
been selected.
There were four complete systems, each consisting of a H-54 and
a B-62, that were tested for a full week, 24-hours a day
in three 8-hour shifts. Each operator would test the machine
for 8 full hours under hot and cold conditions, then sleep
for 8 hours, then perform another 8-hour test and so on.
The machine would be operated non-stop for 24 hours by pressing
random keys on the keyboard.
The tests were carried out south of Munich at Lake Starnberg
(near the Alps) in the shelter (Kofferaufbau) at the back of
a military MAN truck that was parked in front of the building,
guarded by two heavily armed soldiers.
Testing the machines under cold conditions was no problem,
as the test was carried out mid-winter
and the outside temperature was -15 °C.
For the hot condition tests, two large professional hair dryers
were used. They were aimed at the machine until the metal could
no longer be touched.
This process was repeated for 24 hours: one hour cold and one
hour hot. Needless to say that both the H-54 and the B-62
passed all tests with flying colours and that it improved
the operational speed of the H-54 by a factor of 10.
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© Crypto Museum. Created: Sunday 14 April 2013. Last changed: Monday, 28 June 2021 - 06:52 CET.
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