Gretacoder Data Systems
or Gretacoder Data Systems,
was a fully independent manufacturer
of cryptographic equipment, based in Regensdorf
near Zürich (Switzerland).
It was founded by Dr. Edgar Gretener who was not only a direct competitor
of Boris Hagelin, but also worked
with him on a number of occasions.
The company, which also made the encryption devices
for international SWIFT bank transactions, had a world-wide customer base
and had once over 2500 people on its payroll.
Over the years, Gretag produced a range of
commercial, industrial and military cipher machines.
It is known that American intelligence (NSA,
CIA) tried to get control
over the equipment that was produced by Gretag, but to no avail.
As a result, Gretag was regarded a serious threat.
Although the NSA was able to break most of the early machines,
they were not able to read 1 more than 7% of the traffic
encrypted on Gretag cipher machines
that were produced in the late 1970s .
The West-German Bundesnachrichtendienst (BND)
also had a keen eye on Gretag, and regarded the company as their most
serious threat. Unlike its competitor
– Crypto AG – it was not under
control of the CIA and
BND, which meant that their cryptographic algorithms could not
For several years, the BND tried to get a grip on the engineers
and even tried to buy the entire company from its owner Ciba-Geigy,
but to no avail. Gretag remained unreadable to them .
It is known that
the BND launched several smear campaigns against
Gretag, in the hope that potential foreign customers would instead choose
which was owned by BND
The US Central Intelligence Agency (CIA)
was more successful, and got the American telephone company
AT&T to take over the company in 1991.
This gave the CIA full control over the crypto algorithms,
and also over the equipment that was used for the
SWIFT banking network.
The international governmental business had already been passed to
the the Swiss company OmniSec in 1987 .
Eventually, the Gretag business – by then part of
was liquidated in 2004.
➤ Gretag cipher machines
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.
Below is a brief summary of the history of the company, in particular with
respect to the development and production of cipher machines. For a
chronological overview of important events in the history of the company,
we have added a timeline at the bottom of this page.
Dr. Edgar Gretener AG
Gretag AG started life around 1943, when its founder, Dr. Edgar Gretener
established Dr. Edgar Gretener AG in Zürich (Switzerland). Gretener
was one of the developers of the famous Eidophor large
screen video projector that was later marketed by his company .
He became famous for a series of hi-end cipher machines he developed
for the Swiss Army,
and for his wide range of colour image processing equipment for the
printing industry. All equipment manufactured in the early years
carried the name of the founder: Dr. Edgar Gretener AG.
In 1946, the company started the development of
teletypewriters (telex) and
In 1947, a small lightweight teleprinter,
called the ETK-47,
was succesfully introduced and it wasn't before long that
it became widely accepted by the Swiss Army and by small businesses.
In 1949, the Swiss Army expressed an interest in online
cipher machines, resulting in a brief cooperation between Dr. Edgar Gretener
and the Swede Boris Hagelin,
who would later become his competitor.
The result of this joint development was the so-called
also referred to as the GR tg 35, TKG or TC-35 . In 1951, 35 of these
TKG machines were delivered to the Danish Army .
The machine formed the basis for the development of later cipher
machines such as the TC-53 that was designed to work with Gretener's
proprietary ETK-47 teleprinter.
Apart from Dr. Edgar Gretener himself, the key developer of the cipher systems
was Kurt Ehrat who had joined the company on 1 April 1946 .
In the following years, many of the crypto-related patents would be
registered in his name.
The cooperation with Hagelin was not restricted to the Telekrypto 35,
but dates back to 1947, shortly after Gretag had introduced the
Hagelin was particularly interested in these teleprinters,
as they were suitable for his foreign customers.
As the ETK uses a proprietary 14-bit technology to build a character
from the (14) individual segments, it can be modified easily for foreign
languages, such as Russian (Cyrillic), without replacing the print head .
After Dr. Edgar Gretener's untimely death on 22 October 1958,
the company was taken over by the Swiss chemical company CIBA Holding AG
who changed the name to Gretag AG. Dr. Robert Käppeli, one of Gretener's
finiancial backups, became the new director .
Shortly afterwards, the company moved to Regensdorf (near Zürich),
where CIBA had secured a large new premises on an industrial estate
that provided room for expansion. In the following years new buildings
were added and eventually the company would employ over 2500 people.
Even today (many years after the demise of Gretag) the area is known as
the Gretag-Areal .
In 1959, the sales of the Eidophor large screen projectors was spun out of
the company, and moved to the new company EIDOPHOR AG — a joint verture
between Gretag AG and Philips.
By 1962, the company produced over 100 different products in a wide
variety of fields, including cipher machines,
but also devices for the (colour) printing industry.
As this was confusing — not only for the
employees but also for the customers — CIBA decided to divide the many
products into product categories, each of which was supported by a
business group :
- Arc lamps
- Teleprinters, Cipher Machines, electronic devices
- Projection screens
- Digital technology
At this point, Dr. ter Meer was the director of Gretag AG. As part of the
takeover by CIBA, all former Gretag patents were moved to CIBA,
who also managed and monitored them. Some of the early patents were dropped
and some other patents were eventually given back to Gretag AG.
By the late 1960's, Gretag held a respectable number of world-wide patents,
most of which were related to Gretag's ever increasing photographic reproduction
business. Nevertheless, the name of Kurt Ehrat, head of the cipher equipment
development, appears 6th in the list of people with at least five
cryptographic patents in the US, just one place below the famous
William Friedman .
In the early 1970s, it became increasingly difficult to register new patents
as many inventions were declared invalid due to prior art
in a number of countries. In the photographic business there was a stiff
competition with renowned companies
like AFGA, KODAK, Fox-Stanley and CA Pieronex, resulting in legal claims
from these companies, and counter-claims from Gretag.
In the US, it appeared to be very difficult to register patents related
to high-end electronic cipher equipment — such as the
and TC-812 — because of the
Secrecy Act of the Department of Defense. This required the patents to be secret
and blocked the sales of such machines to the general public. For that reason
the patents were not filed in the US, but only in Canada and Japan.
Nevertheless, Gretag kept filing new patents in a variety of fields, and by 1976
they had well over 100 patents in their card index. Head of cryptographic
developments Kurt Ehrat was arguably the most active cryptographic expert
in the company with 23 crypto-related patents in his name,
whilst Robert Wahli was the number one with 39 patents, mainly related
to the photo-business.
In the late 1980s it became clear that Gretag's product range was far too
diverse. Although the crypto-related business was a significant one,
and many new systems had been introduced over time,
it was overshadowed by the photographic business.
In addition, the crypto-business was often linked to
secrecy, espionage and doubtful regimes, and the owner – CIBA – felt increasingly
uncomfortable with that. There was also pressure from Western intelligence
services. On at least one occasion, the BND
had tried to buy Gretag, and there was also pressure from the CIA
In June 1986, CIBA instructed the Gretag board of directors to find
a buyer for the business group 'Authorities' which handled the sales
of strategic equipment to foreign governments and armies.
In June 1987, the board announced that the business unit would be transferred
to the newly established OMNISEC,
also in Regensdorf.
OMNISEC had been founded especially for this purpose and was fully owned
by the all-Swiss ARGONIUM SA, a high-tech holding consortium in Geneva.
The new company was led by Dr. Pierre Schmid, a former employee of
After leading the development of cipher machines for many years,
Schmid had left Gretag in 1978 to start working for
Standard Telephone und Radio AG (STR) in Zürich, the Swiss
subsidary of the American ITT.
At least 7 crypto-related
patents were registered in his name during his time at Gretag .
Approximately 10 Gretag employees were given the option to make the switch
to OMNISEC as well, mainly people from the Intelligence Technology section.
In July 1987, Gretag's customers were informed and OMNISEC officially started
trading on 1 October 1987 .
With the transfer, OMNISEC acquired the production rights of all Gretag
cipher machines, with the exception of the civil cipher machines
and the machines for the Swiss authorities (GRD).
OMNISEC was allowed however, to offer the civil machines abroad as OEM
products. Initially the OMNISEC machines were still manufactured at Gretag,
but over the years, production was gradually moved over to
OMNISEC's own facilities.
Although OMNISEC was successful in the next 25 years,
the company closed its doors in 2018 due to lack of orders.
➤ More about OMNISEC
AT&T / Gretag Data Systems
Being left with just the civil crypto-market, such as banks and the
Swiss Government, the cipher machine division of Gretag AG became
less and less significant. As a result, CIBA finally decided to split-off
the cipher-business altogether, and sold it in 1991 to the large American
Telecom provider AT&T.
The former business unit became a new legal entity:
Gretag Data Systems AG.
Many of the systems developed in the following years,
such as the Gretacoder 524,
would carry the brand name Gretacoder, or
AT&T, or both.
With the acquisition, AT&T had hoped to get a foot in the Swiss market
and get access to systems for safe bank transactions at the same time.
It didn't work out well however, as there was strong competition from
companies like Crypto AG (Hagelin)
and former Gretag-split-off Omnisec AG.
In comparison to AT&T's business in the US, the Swiss operation appeared
to be minute and AT&T gradually lost interest.
IRE / Gretacoder Data Systems
In October 1995, the company was acquired by Information Resource Engineering
Inc. (IRE), a US company that had been established in 1987 by two former
Gretag Data Systems, which had a turnover of $7 million in 1994,
was bought for approx. $4 million  and the name was subsequently
changed to Gretacoder Data Systems AG.
Many new encryption devices were produced during this period, all of which
carried the brand name Gretacoder.
SafeNet Data Systems
In 1999, the current owner of the company – IRE – was renamed to
Safenet, after its VPN product line.
A few years later, in 2002, Gretacoder Data Systems was
renamed to Safenet Data Systems
Due to domestic and international competition, the Gretacoder
business was rapidly declining and SafeNet injected signficanly
new capital in an attempt to turn the tide.
➤ More about SafeNet
Despite the new capital injections, the company did not survive.
Finally, late 2004, the board of directors saw itself forced to
announce immediate liquidation of the company.
The former Gretag buildings at Althartstraße in Regensdorf
are still standing today and still carry the name of the once
so large company. The estate is now called Gretag-Areal and
the buildings are rented in small units to a wide range
of different companies . Gretag-Areal is headed by Felix Ruhier,
who was once a Group Controller at Gretag (1991-1993) .
When Dr. Edgar Gretener founded his company in 1943, there was no official
company logo, and all official documents, offerings, brochures, etc.,
were signed with the name
Dr. Edgar Gretener Aktiengesellschaft.
In the late 1940s, the first official company logo appeared, as shown above.
It is basically a monogram with the initials of Dr. Edgar
Gretener – EG – merged into a circle. The image
on the right shows an original cliché of 1957, that was used for printing
the company's stationary and the front pages of the manuals.
In 1958 – after Gretener had passed away unexpectedly – the company was sold to
CIBA Holding AG and the name was changed to GRETAG AG. At the same time,
the old monogram-logo was replaced by the word 'GRETAG', printed
double-spaced in a Palatino typeface, as shown below.
In the late 1970s the name GRETACODER was introduced and the company name on
some of the brochures was changed to GRETAG COMMUNICATIONS SECURITY,
printed in a Futura-ExtraBold typeface,
accompanied by an uninspiring blue logo of a punched paper tape with a
In the following years, probably in the mid-1980s, the logo above
was replaced by a stylized line-art drawing of a blue cubical G with the
word GRETAG printed below it in a hand-crafted angular typeface.
This is the final logo that was used until the demise of the company in 2004.
Below is an overview of important events in the history of Gretag in
chronological order. It also highlights some of the attempts of foreign
intelligence agencies – in particular CIA and BND –
to get control over Gretag. Given the context
in which the events took place, it seems reasonable to assume that the
take over of Gretag by AT&T in 1991, was orchestrated to put the CIA
Gretag, or Gretacoder Data Systems AG, is no longer in business
and support for old Gretag equipment is non-existent
The last known addresses are:
- Dr. Edgar Gretener AG (1943)
- Gretag AG (1958)
- Gretacoder Data Systems AG (1995)
- SafeNet Data Systems AG (2002-2004)
- Ulrich Rimensberger, Datensicherung durch Chiffrierung
Description of the Gretacoder 515, published at the 5th International
Congress for Data Processing in Europe. Vienna, 21-25 March 1977.
- Gretacoder Data Systems AG. Gretacoder 650, High-Speed Link Encryptor.
2-page sales brochure. August 2000.
- Gretacoder Data Systems AG. Gretacoder 545, X.25 Data Encryption.
4-page sales brochure. April 1997.
- The Free Library, IRE Acquired Gretag Data Systems AG
11 June 1995, Retrieved march 2012.
- Dr. John H. Nugent, Curriculum Vitae
Member of Board of Directors at AT&T Gretag 1991-1993.
31 March 2007. p. 6.
Retrieved March 2012.
- Business Wire, SafeNet to Expand and Strengthen European Operations...
Business Library website. Retrieved July 2012.
- Wikipedia Germany, Edgar Gretener
Retrieved May 2013.
- Dr Edgar Gretener AG, Telekrypto-Gerät GR tg 35
Gretag Archives, 1949-1951. Crypto Museum #CM301792.
- Gretener AG, Besprechnungsnotiz vom 30. März 1951
Minutes of meeting concerning delivery of 35 TKG machines to Danmark (German).
Gretag archives, 3 April 1951. Crypto Museum #CM301792/A.
- Gretag AG, Personalmutation Kurt Ehrat
Interial memo about Kurt Ehrat reaching retirement age (German).
Gretag Archives, 31 January 1979. Crypto Museum #CM301766.
- Schweizerische Bauzeitung, Edgar Gretener. 3 March 1957 - 22 October 1958.
Obituary (German). 76th edition, Volume 51. 20 December 1958.
- Letter from [Oskar] Sturzinger (Hagelin) requesting Cyrillic characters for the ETK-47
21 March 1947. Retrieved from .
- Walter Schmid, Der Krypto-Funk-Fernschreiber KFF-58
Gretag Areal, Regensdorf, Zurich 1
Website of the current land owner of the former Gretag buildings.
Retrieved July 2013.
- CIBA AG, Aufteilung der Gretag-Cases in die verschiedenen Sachgebiete
Creation of Gretag operational divisions (German). Gretag Archives.
Basel, 17 December 1962. Crypto Museum #CM301793.
- US Patent Office, List of inventors with at least five (cryptographic) patents
Date unknown, but likely to be 1968.
- Gretag AG, "Leitfaden" zur Info-Weitergabe am 29.7.87
Memorandum about the transfer of cipher equipment to OMNISEC AG (German).
29 July 1987. #CM301765/A.
- Crypto Museum, Gretag AG Patents
Complete overview and correspondence regarding Gretag Patents 1943 - 1990.
Gretag Archives, Crypto Museum #CM301767.
- Linked-in, Felix Ruhier
Retrieved July 2013.
- Crypto Museum, Operation RUBICON
- Gretag & Omnisec, Announcement to customers and agents
29 July 1987. #CM301765/B.
- Wikipedia, Eidophor
Retrieved November 2020.
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© Crypto Museum. Created: Thursday 05 July 2012. Last changed: Saturday, 28 November 2020 - 13:17 CET.