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Crypto AG Data BND CIA HC-500 series →
The image on the right shows a typical HC-550, which is nearly identical
to the Siemens T-1000 telex
it is based on. In this case, the machine
has a tape reader to the right of the keyboard and a tape puncher bolted on
at the right. Suitable five-level paper tape should be fed in from the rear.
The machine itself prints its output directly onto a paper roll
that is also fed in from the rear.
A black slimline metal cabinet is mounted to the bottom of the teleprinter.
At the front are two physical keys, one for entering the cryptographic
key and one for selecting the mode of operation.
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The HC-550 is an off-line machine, whilst the HC-580 can also be used on-line.
Both machines can also be used as an ordinary
teleprinter
when used in a line-connected mode. The teleprinter
is only used as an input/output device, or terminal,
whilst the cipher unit at the bottom bottom takes care of the
actual encryption, similar to
the Philips Aroflex
and Timmann's TST-9669-11.
Note however, that the Hagelin HC-550 is not compatible with
either of these two machines.
The use of a standard teleprinter
greatly simplifies the design and allows
different typefaces to be used, such as Latin, Arabic, Farsi, etc.
Furthermore, this machine can print on ordinary paper, unlike the
HC-570
which prints on thermal paper. The advantage of the
HC-570 on the other hand,
is the higher speed at which it can process and print its data.
The machines are compatible,
and were available in two cryptologic-variants, one of which
could be broken by NSA and BND
[2].
The readable one was improved later, when it was found to be
prone to known plaintext attacks.
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The diagram below shows a typical Hagelin HC-550 in operation. The machine
has all features of a standard
Siemens T-1000 teletypewriter,
including an
external paper tape puncher mounted at the right. The actual cipher
machine is mounted under the T-1000. It is operated through two physical
keys and 6 push-buttons at its front panel. Additional features are available
through the special function keys of the T-1000, some of which are not
present on a regular T-1000 telex.
To operate the machine, the leftmost physical key is used to enter
the Basic cryptographic Key (BK). The key is used to toggle between BK
and operational mode.
Turning the key in the opposite direction, allows the machine to be opened,
much like the motor compartment of a car. The rightmost physical key is marked
C/D and is used to toggle between ciphering and deciphering.
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Compatible machines
Cryptomatic 500
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Similar machines
not compatible with Cryptomatic 500
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The HC-550 was developed at a time when
the company – Crypto AG – was jointly
owned by the German Bundesnachrichtendienst (BND)
and the American Central Intelligence Agency (CIA).
The two intelligence services had purchased the company in 1970,
with the intention to get control over the cryptographic algorithms
and — indirectly — Crypto AG's customers. This secret project was known as
Operation RUBICON (also: THESAURUS)
and turned out to be extremely effective [2].
The first machine of the 500-series
– HC-570 –
was the successor to the ill-fated H-460,
Crypto AG's the first fully electronic cipher machine,
that had been introduced just before BND
and CIA became the owners of the company.
It used a shift-register-based cryptologic, that had been
designed by the NSA in 1966, in such a way that messages were
readable 1 to them.
When BND
and CIA took over, it was decided that
Crypto AG should sell
high-end cipher machines that could compete with the designs from
other manufacturers,
such as Gretag,
that were not under control.
The new machine was designated HC-570
and was partly designed in-house by Crypto AG,
whilst Motorola was hired to do the
design of the microprocessor-based cryptologic.
The cryptographic algorithm was supplied by the
US National Security Agency (NSA).
The machine was introduced in early 1977, but did not become very popular.
It was difficult to build, complicated to operate and expensive.
A few years later it was replaced by the HC-550, which became an
instant hit. There was also a portable version,
the HC-520,
that was meant as a competitor
to the Gretacoder 905.
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In February 1979, less than two years after the introduction of the
HC-500 series, CAG-employee
Jürg Spörndli,
discovered that it was
possible to break the machine with just 100 characters of known
plaintext, probably after attending a seminar by American mathematician
Martin Hellman.
Although rather theoretical, it proved that the cipher was prone to
a known plain-text attack, or KPTA as it was known in the cryptologic world.
To Crypto AG this was bad news,
as the company couldn't afford another
debacle after the H-460 crisis.
In two years time, the HC-500 series had
become Crypto AG's leading product,
of which more than 1700 had already been sold worldwide.
The original algorithm had been developed by
NSA's Peter Jenks,
and was intended to last for at least 20 years. But Jürg Spörndli had
now exposed a weakness, whch urgently needed to be fixed before customers
would discover it themselves. At NSA,
Dave Frasier designed a
drop-in fix that defeated a known plaintext attack, but was
considerably more difficult to break by NSA
and ZfCh.
A few months later, mid-1979, Peter Jenks
left the NSA and Dave Frasier
committed suicide.
➤ More about Operation RUBICON
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In this context, readable means that the cryptographic algorithms
could be broken by the NSA.
Also known as friendly. In contrast:
algorithms that are not breakable by NSA,
are called unfriendly or unreadable.
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The Hagelin HC-550 cipher machine is mounted to the bottom of the
Siemens T-1000 telex,
with a hinge at the rear acting as a pivoting point.
The interior can be accessed by turning
the leftmost physical key at the black front panel counterclockwise.
This unlocks a latch at the front centre.
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Once the latch is unlocked, the teleprinter can be tilted backwards
by lifting it at the front. After tilting the machine by approx. 45°,
a metal stub at the right can be raised to prevent the machine from
falling back, in a similar manner as the hood of the engine
compartment of a vehicle.
Inside the device are two large printed circuit boards (PCBs), each of which
takes up about half the available space. The PCB at the front holds
the microprocessor, the I/O interface and some logic, whilst the board at
the rear holds the RAM memory and the EEPROMs with the firmware.
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The cable at the front right connects the cryptologic
to the push-buttons at the front panel.
At the left is a
small PCB that is mounted to the side.
It holds a 15-pin sub-D test connector and button marked EMCY (emergency).
It is covered by a protective black plastic cap and acts as the
co-called ZEROIZE-button.
Pressing it, clears
the memory and purges the cryptographic keys.
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The cryptologic was developed at the secret Government
Electronics Division of Motorola
in Phoenix, at the request of the NSA
and CIA. In order to hide their true identity from Motorola
engineers, NSA
and CIA officers pretended to be working for
cover company Intercom Associates,
when they visited the plant in Phoenix (Arizona).
Motorola
was hired in 1974, after the NSA
had failed to do the design itself. When the
prototypes were delivered in 1975, it was probably the first time
an algorithm had been implemented entirely in
software, in a small microprocessor.
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The image above shows the MC6800 microprocessor, that had just been
introduced by
Motorola
in 1974 [3].
The actual algorithm — developed by
Peter Jenks at the NSA —
was implemented in software and was held in a
set of EPROMs. 1
Motorola
also acted as a cover for the NSA, so that it would not
be obvious to Crypto AG engineers that the
algorithm was influenced by the NSA
[2].
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EPROM = Erasable Programmable Read-Only Memory.
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- Mode: off-line
- Line input: Receipt of cryptograms via lines
- Basic key: 7 keys can be stored, each with 1028 variations
- Message key: 1.4 x 10 variations.
- Period: 1054 steps
- Memory: 8000 characters
- Speed: 50, 75 or 100 baud
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- Mode: off-line and on-line
- Line input: 7 and 7½ unit start/stop (plain or cipher text)
- Basic key: 21 keys can be stored, each with 1028 variations
- Message key: 1.4 x 10 variations.
- Period: 1054 steps
- Memory: 8000 characters
- Speed: 50, 75 or 100 baud
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© Crypto Museum. Created: Friday 22 April 2016. Last changed: Friday, 04 February 2022 - 10:21 CET.
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