Spy sets
Burst encoders
Logo (click for homepage)
Gretag, or Gretacoder Data Systems, or simply Gretacoder, was a 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, who 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.
Gretag company logo

Over the years, Gretag produced a range of commercial, industrial and military cipher machines. The company changed hands several times and was eventually split up into different companies. In 2004, the crypto-part was dissolved when it was owned by SafeNet. By that time however, most of its patents had already been transferred to Omnisec, who are still in business today.

Gretag's cipher machines are known under different names and numbers. Generally speaking, the numbering was never changed, but different prefixes and brand names were used. The name Gretacoder was sometimes abbreviated as 'GC' or 'TC' (for: Tele-Crypto, or Teleprinter Crypto). E.g.: the military 812 telex encryption unit is known as Gretacoder 812, GC-812 and TC-812.

 More about Gretag (history)
The following Gretag cipher machines are featured on this website:
Telekrypto-Gerät 35, developed by Edgar Gretener (Gratag) and Boris Hagelin. TKG 35 One of the first electro-mechanical cipher machines build by Gretener TC-53 Gretacoder 101, speech scrambler GC-101 Gretacoder 103, telephone scrambler GC-103 Gretacoder 104, voice scrambler GC-104 Gretacoder 805 (portable version) GC-805 Gretacoder 805 (desktop version) GC-805
Gretacoder 524 link encryptor (64 kb/s) GC-524 Gretacoder 603 GC-603 Gretacoder 605 link encryptor (2048 kb/s) GC-605 Gretacoder 720, extremely secure DES encryptor for SWIFT transactions GC-720

TKG 35   wanted item
Telekrypto-Gerät 35 (TKG) was an online cipher machine for Gretag's proprietary 14-bit teleprinters, such as the ETK-47. It was a joint development of Dr. Edgar Gretener (Gretag) and competitor Boris Hagelin and used Hagelin's pin-wheel system.

 More information

The TC-53 was the first electro-mechanical cipher machine manufactured by Gretag for the Swiss Army. It was based on an earlier design of Dr. Edgar Gretener and competitor Boris Hagelin.

The machine had 12 cipher wheels and used a novel 14-bit technique, rather than the usual 5-bits for transmission of the data.

 More information
TC-53 without the SPG key generator

Gretacoder 101
The Gretacoder 101, or GC-101, was a modular speech scrambler for telephone and radio links, introduced in 1975. It uses two-dimensional voice scrambling and was based on the earlier SC-101 from 1973.

The device is suitable for half-duplex only, which is controlled by a Push-To-Talk (PTT) switch in the handset.

 More information
Gretacoder 101

Gretacoder 103
The Gretacoder 103, or GC-103, was a voice scrambler for analogue telephone lines. It is inserted between the phone and the line.

It uses time-domain as well as frequency-domain scrambling and was manufactuered as an OEM product by Telsy in Italy. It is identical to the Telsy TDS-2004.

 More information
Telsy TDS-2004

Gretacoder 104
The Gretacoder 104, or GC-104, was a voice scrambler for mobile use. It uses time-domain as well as frequency-domain scrambling and was manufactuered as an OEM product by Telsy in Italy. It is identical to the Telsy TDS-2004M.

 More information

Gretacoder 805   portable
The Gretacoder 805 was a small portable electronic cipher machine that was fitted inside a standard Samsonite briefcase, together with a small thermal printer.

 More information
Gretacoder 805

Gretacoder 805   desktop
As the Gretacoder 805 had a highly modular design, a variety of different configurations were possible. For the office, a large desktop version could be created, complete with a papertape reader/puncher ans shown here.

 More information
Complete Gretacoder 805 desktop system with paper tape reader/puncher on the left

Gretacoder 524
Gretacoder 524 was a line encryptor for synchronous (RS-232) serial links, developed in the early 1990s when Gretag was part of AT&T. It supports continuous data encryption at rates up to 64 kb/s and was available with various interfaces and (software) options.

 More information
Gretacoder 524

Gretacoder 603
This 19" rackmount system, consisted of two units. One for either side of the communication link. It was used to encypher and decypher multiplexed data streams over satellite links.

 More information

Gretacoder 605
Gretacoder 605 was a line encryptor for synchronous (RS-422) serial links, developed in the mid-1990s when Gretag was part of IRE (Now: SafeNet). It supports continuous data encryption at rates up to 2048 kb/s and was available with various interfaces and options.

 More information
Gretacoder 605

Gretacoder 720
Gretacoder 720 was a highly secure DES encryptor for international bank-to-bank payments (SWIFT). It was housed in a large strong 19" case and was highly tamper-proof.

 More information
Gretacoder 720

Known Gretacoder systems
Below is a non-exhaustive overview of the various Gretag encryption devices we've encountered so far. Initially all machines were built under the Gretag brand. Later the name was changed to Gretacoder, which was sometimes abbreviated as 'GC'. In the overview below, 'GC' stands for Gretacoder, whilst 'TC' probably stands for 'Tele Crypto' or 'Teleprinter Crypto'. If you know any model that is not listed here, please let us know.
  • Gretag TC-53
    Electro-mechanical cipher machine for use with teletype equipment. 1950s.

  • Gretag TC-58
    Electro-mechanical cipher machine with cipher wheels, that was used in combination with the Gretag KFF teleprinter. The complete unit was known as the KFF-58.

  • Gretag TC-61
    Later version of the TC-58, with the only difference being the addition of a random number generator on the front panel. The latter was used for the generation of message keys.

  • SC-101
    Speech scrambler, for telephone and radio traffic. Based on the principle of speech inversion. Built around 1973.

  • Gretacoder 101
    Voice scrambler for secure telephone and radio traffic. Based on the earlier SC-101 and introduced in 1975.

  • Gretacoder 102
    Military version of the Gretacoder 101. 1975.

  • SC-201
    Speech encryption device, built in 1976. Gretacoder 202/index.htm Speech encryption device, built in 1977. Gretacoder 210-210/index.htm Voice encryption device. Built around 1980.

  • Gretacoder 505 / SP300 GCA
    Teleprinter cipher system. Compatible with the Gretacoder 805.

  • Gretacoder 515
    Continuous block cipher system, for use on digital data networks. Intended for use by banks, large corporations and public services. The built-in V.24 modem supports all data speeds up to 20 kbit/sec. Allows the connection of asynchronous terminals and teletype equipment (CCITT alphabet #5), synchronous terminals and computers, both in half duplex and full duplex. Developed for SWIFT around 1974 and introduced in 1977 [1].

  • Gretacoder 517
    Data encryptor. Built around 1979.

  • Gretacoder 518
    Link encryptor. Further details currently unknown.

  • Gretacoder 524
    X.21 Data encryption system for corporate networks, with a maximum data transfer speed of 64 kb/s, using synchronous RS-232 protocols.

  • TC-534
    Early speech encryption system, developed around 1964, consisting of two large (military) cases. Built around the first digital circuit blocks. Later redesigned with TTL logic.

  • Gretacoder 545
    X.25 Data Encryption system [3] for corporate data networks. April 1997.

  • Gretacoder 549
    X.25 On-line Network Security Center (NSC) [3]. Secure host system for communication with Gretacoder 545 nodes in corporate networks. April 1998.

  • Gretacoder 555
    Frame Relay Encryptor with a high level of security.

  • Gretacoder 601
    Military-grade continuous block cipher system, for use on high-speed multiplexed data networks. Suitable for the transmission of computer, fax and voice data over (satellite) networks. The civil version is known as GC-603.

  • Gretacoder 603
    Continuous block cipher system, for use on high-speed multiplexed data networks. Suitable for the transmission of computer, fax and voice data over satellite networks. Civil version of the GC-601.

  • Gretacoder 605
    V.35 Data encryption systems for corporate networks, with a maximum data transfer speed of 2048 kb/s, using synchronous RS-422 protocols. It is backwards compatible with the Gretacoder 524.

  • Gretacoder 650
    High-speed Link Encryptor in 19" rack mount, providing full-duplex synchronous link encryption with data rates of 34 and 45 MBits/sec (E3 and T3). Can be used in protocol-transparent mode (continuous encryption) or in protocol-dependent mode (framed encryption) [2] . August 2000.

  • Gretacoder 700
    Highly secure encryption/decryption system for Italian inter-bank payments (SIA). Developed around 1989. Very similar to the later Gretacoder 720.

  • Gretacoder 715
    Highly secure encryption, decryption and authentication system for Swiss inter-bank money transactions (SIC), developed around 1989.

  • Gretacoder 720
    Highly secure encryption systems for international bank transfers (SWIFT), as used by all banks world-wide during the 1990s and 2000s. Suitable for serial RS-232 and X-25 protocol data, and extremely well protected against tampering.

  • Gretag TC-800
    Off-line electronic cipher machine, developed in 1969. Probably a prototype of the later TC-803.

  • Gretag TC-803
    Semi-portable off-line electronic cipher machine in samsonite briefcase, with separate 5-level paper tape reader/puncher.

  • Gretacoder 805 (portable version)
    Modular electronic cipher machine for the encryption of short written messages. It was available in a portable version and in a desktop version, and a large number of options were available.

  • Gretacoder 805 (desktop version)
    Desktop version of the above.

  • Gretag TC-812
    Military grade data encryption unit for use with teleprinter signals (telex). Developed around 1969.

  • Gretacoder 905
    Pocket electronic text encryptor with a LED array and a few buttons. Compatible with the Gretacoder 805 and with the later Gretacoder 906. Built around 1974.

  • Gretacoder 906
    Pocket electronic text encryption device with full keyboard and LCD screen. Compatible withe the Gretacoder 805 series and with the earlier Gretacoder 905.

  • Gretacoder 915
    Off-line authenticator for banks. Developed in 1975.

  1. 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.

  2. Gretacoder Data Systems AG. Gretacoder 650, High-Speed Link Encryptor.
    2-page sales brochure. August 2000.

  3. Gretacoder Data Systems AG. Gretacoder 545, X.25 Data Encryption.
    4-page sales brochure. April 1997.

  4. The Free Library, IRE Acquired Gretag Data Systems AG
    11 June 1995, Retrieved march 2012.

  5. 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.

  6. Walter Schmid, Der Krypto-Funk-Fernschreiber KFF-58
    October 2008.

Further information

Any links shown in red are currently unavailable. If you like this website, why not make a donation?
© Copyright 2009-2013, Paul Reuvers & Marc Simons. Last changed: Friday, 07 March 2014 - 21:37 CET
Click for homepage