The device is based on the (unbreakable)
One-Time Pad (OTP) system
and offers 2 compatibility modes: modulo 26,
for backwards compatibility with mechanical RT/CX machines,
and modulo 31 for use between two ULES-64 machines
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.
ULES-64 marks Crypto AG's transition from (electro)mechanical
OTT cipher machines, such as
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
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 .
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 they were used alongside the Dutch-built
Philips Ecolex II
and Ecolex IV, with which they were not
compatible. It is therefore likely that the Dutch bought the machines
for backwards compatibility with their existing
The machines were supplied via the Dutch Hagelin distributor:
Koopman & Co. in Amsterdam. 2
Before 1960, Hagelin had a secret
gentleman's agreement with the
US National Security Agency (NSA), but this
was superceeded in 1960 by a written
licencing agreement with the
CIA, under the codename SPARTAN.
It is possible that the ULES-64 was bought because the Ecolex machines
were in short supply, but this is unlikely, as the Ecolex was initially
developed exclusively for the Dutch Government. It might also have been
a compensation order, as Hagelin
with the NSA to sell these machines to friendly nations only.
- CR — modulo 26
In this mode the machine is backwards compatible with the mechanical RT/CX
machines. 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
such as the Philips Ecolex II.
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:
VVe.g. Spanish, Italian
Like most ULES-64 machines, the one shown here has undergone a few
modifications over time. 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.
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), is 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.
So far, we have recorded the following modifications:
- New carrying handles at the sides
- Rear panel replaced by metal grid
- ULES 64, Vorläufige Kurzbeschreibung
No. 1193. Preliminary brief description (German).
Crypto AG, Oskar Sturzinger, 6 January 1966. 1
- ULES-66, Circuit Diagrams
Crypto AG, 1963-1965.
Document kindly provided by  and optimised by Crypto Museum.
- Anonymous, ULES-64 background information
Retrieved June 2019.
- Crypto AG, personal correspondence
Crypto Museum, March 2019.
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© Crypto Museum. Created: Friday 26 October 2018. Last changed: Sunday, 10 May 2020 - 08:30 CET.