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OTT Crypto AG
The device is based on the (unbreakable)
One-Time Pad (OTP) system
and offers 2 compatibility modes: modulo 26,
for backward compatibility with mechanical RT/CX machines,
and modulo 31 for use between two ULES-64 machines
[A].
The machine is not small. It measures 650 x 365 x 356 mm and weights
no less than 35 kg.
It has two 5-level tape readers at the top surface
– one for the message and one for the key tape –
and is intended for off-line use only. The device is suitable for data speeds
of 50, 75 and 100 baud, selectable by swapping one of the circuit boards.
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ULES-64 marks Crypto AG's transition from (electro)mechanical
OTT cipher machines, such as
the C-446/RT,
CX-52/RT,
and TC-52,
to fully electronic ones, in which the tape readers are the only moving parts.
As these devices are theoretically
unbreakable — they are based on the
One-Time Pad (OTP) system —
they were only supplied to friendly nations and were omitted from
Hagelin's public brochures, as per
secret licencing agreement
with the
Central Intelligence Agency (CIA). 1
As the name suggests, development of the ULES-64 started in late 1964 and took
slightly more than one year [2].
It was officially released in January 1966 [A]
and the Dutch Ministry of Foreign Affairs was one of its first users.
This is remarkable, as it was used alongside the Dutch-built
Philips Ecolex II
and Ecolex IV, with which it was not
compatible. It is therefore likely that the Dutch bought the machines
for backward compatibility with their existing
C-446/RT machines.
The machines were supplied via the Dutch Hagelin distributor:
Koopman & Co. in Amsterdam.
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- CR — modulo 26
In this mode the machine is backward compatible with the
mechanical RT/CX machines
and the electronic Dutch Ecolex I.
Only the 26 letters of the (Latin) alphabet can be encrypted, and the
SPACE-character has to be replaced by one of them. In the German version,
the letter 'X' was used for 'SPACE'. In this mode, the 5 channels of the
paper tape are weighted.
- MG — modulo 31
In this mode, all 31 characters of the
ITA-2 telegraphy alphabet
are supported, although some of them are are passed unaltered, and some
are replaced by blanks. This ensures a properly formatted output,
but makes the machine incompatible with contemporary
mixers like
ETCRRM
and Ecolex II.
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When used in modulo-26 mode, one of the 26 letters of the
alphabet is assigned as replacement for the space character. This
character can not be used as part of the text. Based on the language
(and the wishes of the customer) the least frequently used letter will
be assigned for this. If it occurs in a text, it should be replaced by
another letter, or by two other letters, for example:
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W VV e.g. Spanish, Italian X KS e.g. German, Dutch Z TS e.g. English K CC e.g. French
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Only five units of the relay-based Colex were built,
before it was succeeded by the Ecolex I.
Although Ecolex I was faster then Colex,
it was a complex and expensive machine — it contained 70 thermionic valves
(tubes) — which was largely caused by the fact that it had to be
backwards compatible with the
26-letter C-446/RT [3].
Only 25 - 50 Ecolex I units were manufactured .
The Dutch therefore decided to develop another version of the Ecolex,
which could encrypt all 32 characters of the
ITA-2 telegraph alphabet.
This would make the machine simpler and cheaper, but would not be
backwards compatible with older machines. Development of the
Ecolex Mark 2
started in 1953 — first with valves, later with transistors — and resulted
in 1954 in Ecolex II, of which approx. 120 units were
manufactured.
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The Ecolex II
was not only used by the Dutch Foreign Office, but also by the
Armed Forces, as a result of which a limited number was available for
embassy traffic. As a result, some of the smaller embassies still had to use
the old mechanical C-446/RT or
compatible hand methods.
It is likely that ULES-64 machines were ordered by the Dutch to replace the
valve-based Ecolex I machines, as a gap-fill solution until
better equipment would become available. Development of newer machines
continued in The Netherlands, but took much longer than anticipated.
Finally, from 1976 onwards, all cipher machines
for embassy traffic were replaced by the Aroflex.
This is corroborated by former Dutch Ambassador to Argentina Ben Bot,
who recalls having worked with
manual Hagelin machines (C-446/RT),
which were replaced in the mid 1970s by
Aroflex [4].
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Like most ULES-64 machines, the one shown here has undergone a few
modifications:
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- New carrying handles at the sides
The most abovious one is the replacement of the
carrying handles at the sides. As the original hinged ones were not strong
enough to carry the rather heavy machine, they were replaced by strong
window grips from a local hardware store.
- Rear panel replaced by metal grid
Another problem with the ULES-64 was related to temperature.
As the device is built with the first generation Integrated Circuits (ICs)
based on the so-called Transistor-Transistor-Logic (TTL), it generates a lot
of heat. For this reason, the back panel was often replaced by a metal grid,
so that the internal parts had sufficient cooling.
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- ULES 64, Vorläufige Kurzbeschreibung
No. 1193. Preliminary brief description (German).
Crypto AG, Oskar Sturzinger, 6 January 1966. 1
- ULES-64, Circuit Diagrams
Crypto AG, 1963-1965.
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Document kindly provided by [1] and optimised by Crypto Museum.
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© Crypto Museum. Created: Friday 26 October 2018. Last changed: Monday, 06 March 2023 - 11:20 CET.
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