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Data
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Philips
  
Ecolex X →
← Ecolex IV
  
Tarolex 19"
Online key generator

Tarolex was a key stream generator for a modified Ecolex IV cipher machine, developed in 1966 by Philips Usfa in Eindhoven (Netherlands) for the Royal Dutch Army. It was introduced in 1967, and allows a modified Ecolex IV machine to be used with a pseudo-random key stream, rather than with an One-Time Tape (OTT). The machine was initially designated Ecolex V, but was re­named Tarolex in December 1962. The machine is also known as UA 8084 and KL/TGA-3128.

A complete tarolex system comprises the Tarolex key stream generator, a regular teletypewriter (telex) and a modified Ecolex IV cipher machine. The image on the right shows the bare Tarolex key stream generator with the access door to its control panel open. The lower part of the control panel (the grey rectangle) holds the key tape reader.

Tarolex is housed in a heavy TEMPEST proof enclosure as is clearly visible in the photographs below. The actual key settings are behind a door on the right half of the unit (see below).
  

Tarolex was developed at the request of the Royal Dutch Army, who wanted a solution for the key-tape distribution problem of the existing mixer machines, such as the Ecolex IV and, to a lesser extent, Its predecessor Ecolex II. In order to be able to connect Tarolex in place of the existing key-tape reader, a suitable interface was developed as well [2].

Tarolex was based on the design of TROL, that was developed between 1962 and 1965 for a NATO evaluation. TROL was never built however, as Philips lost the evaluation to BID/610 (ALVIS) [2]. Tarolex is in fact a combination of the separate items that TROL consisted of. The name TAROLEX was also derived from TROL and stands for Tapeless Rotorless Online Encryption. The suffix 19" to the name was used to discriminate the machine from the earlier TROL development.

Although development of the Ecolex X had already started in 1965, it was clear that it would not be ready before 1972. Tarolex was therefore used as a gap-fill solution until Ecolex X was ready. In total, 151 Tarolex 19" units were built. Nevertheless, many Tarolex units remained in service after the Ecolex X was rolled out in 1972.

Tarolex front view
Tarolex with access door closed
Tarolex main unit
Control panel
Key tape reader - closed
Key tape reader - open
A
×
A
1 / 7
Tarolex front view
A
2 / 7
Tarolex with access door closed
A
3 / 7
Tarolex main unit
A
4 / 7
Control panel
A
5 / 7
Key tape reader - closed
A
6 / 7
Key tape reader - open
A
7 / 7
7 / 7

Setup
The image on the right shows a complete Tarolex setup [1]. The Tarolex itself is the 19" unit at the bottom right. On top of the Tarolex is a standard Siemens T-100 teletype machine.

The modified Ecolex IV is at the left. The rear tape reader (that was used for the key tape) is replaced by an interface with a connector. A cable runs from the connector on the Ecolex IV to the front of the Tarolex. This way, the key stream, generated by Tarolex, is fed to the Ecolex IV instead of the usual random key-tape.

Tarolex is housed in a heavy TEMPEST proof enclosure as is clearly visible in the photographs below. The actual key settings are behind a door on the right half of the unit (see below).

  

Possible setup with Tarolex
Possible setup with Tarolex
Close-up of the controls and the tape reader
Close-up of the tape reader
Unknown rack with serveral units, including a Tarolex. Prabably a test setup.
Early prototype of Tarolex 19
Early prototype of Tarolex 19
Testing an early prototype of Tarolex 19
Rear view of an early prototype of the Tarolex 19
B
×
B
1 / 9
Possible setup with Tarolex
B
2 / 9
Possible setup with Tarolex
B
3 / 9
Close-up of the controls and the tape reader
B
4 / 9
Close-up of the tape reader
B
5 / 9
Unknown rack with serveral units, including a Tarolex. Prabably a test setup.
B
6 / 9
Early prototype of Tarolex 19
B
7 / 9
Early prototype of Tarolex 19
B
8 / 9
Testing an early prototype of Tarolex 19
B
9 / 9
Rear view of an early prototype of the Tarolex 19

Daily key settings
The principle behind the Tarolex is that a short key is used to generate a longer key. Inside the machine is a complex Pseudo-Random Number Generator (PRNG) that generates an evenly spread, difficult to predict, stream of characters with a very long period. The latter means that it does not repeat itself for quite a long time. The key tape is used as the so-called seed.

Behind the door on the right half of the front panel are the controls and, more importantly, the key tape reader. Although the unit was fed with a standard 5-level piece of punched tape, it is not a tape reader in the usual sense. Rather than running through the reader and reading the characters one-by-one, Tarolex reads all characters from the key tape at once.

The tape reader itself, consists of yet another 'door' behind which 110 pins are located. These pins are used to read the key tape that is 22 characters long (22 x 5 bits = 110 bits). As a result, there are 2110 possible combinations, which is approx. 1033.

The image on the right shows the opened tape reader of the Tarolex. The 110 pins of the reader are clearly visible in the bottom half of the image. The pins are arranged in the same pattern as on a standard punched paper tape. Once the tape was in place and all doors were closed again, Tarolex was ready for use.
  

The advantage of the combination Ecolex IV and Tarolex was that, in synchronous mode, the system kept sending a cipher stream, even when no new information was typed on the teletype unit. This way, it was impossible for an interceptor to determine the start or end (and hence the length) of a message. Furthermore, it was impossible to recognize the operator from his or her typing speed.


Parts
Tarolex key generator
Modified Ecolex IV cipher machine
Siemens T-100 teletypewriter
Interconnection cable between Tarolex and modified Ecolex IV
Key tapes
Operating instructions and technical description
Tarolex key generator
The heart of the system is the Tarolex key generator shown in the image on the right. It consists of an electronic pseudo-random generator that is seeded by a short piece of 5-bit key tape, installed in a key tape reader behind alocked door.   

Modified Ecolex IV
The Tarolex key generator was used in combiation with the modified Ecolex IV cipher machine shown in the image on the right. This is basically a standard Ecolex IV of which the rearmost tape reader has ben replaced by an interface. Tarolex is connected to this interface.   

Siemens T-100 teleprinter
For input and output of text, a common Siemens T-100 teleprinter (telex) was connected to the modified Ecolex IV. This allowed Tarolex to be used in existing fixed and mobile installations that had until then been running on a regular Ecolex IV with T-100.

 More information

  

Interconnection cable
The cable shown in the imge on the right was used to connect Tarolex to the interface of the modified Ecolex IV.

  

Key tapes
Keys were supplied for several days in advance, in a metal tape cartridge such as the one shown in the image on the right. Each tape holds a number of key segments, each of which can be installed in the Tarolex tape reader.

The tape consists of a readable Tape ID, which is punched into the start of the key tape. Each key segment is preceeded by a sequential segment number, which is also punched into the key tape in readable form. The key segment itself consists of 22 characters of 5-bits each. It must be placed in the key tape reader of the Tarolex.

  

Manuals
...

 User manual (Dutch)
 Technical manual (Dutch)

  

Tarolex main unit
Tarolex key tape cartridge
Tarolex key tape cartridge with key tape segment
Sealed cartridge
Key tape ID
Segment ID
Key segment
C
×
C
1 / 8
Tarolex main unit
C
2 / 8
2 / 8
C
3 / 8
Tarolex key tape cartridge
C
4 / 8
Tarolex key tape cartridge with key tape segment
C
5 / 8
Sealed cartridge
C
6 / 8
Key tape ID
C
7 / 8
Segment ID
C
8 / 8
Key segment

Specifications
  • Device
    Key stream generator
  • Purpose
    Encryption of military teleprinter traffic
  • Model
    Tarolex
  • Designator
    UA-8084
  • NL Army
    KL/TGA-3128
  • Manufacturer
    Philips Usfa
  • Development
    1966-1967
  • In use
    1967-1982+ 
  • User
    Royal Netherlands Army
  • Key length
    110 bits
  • Interface
    5-bit teleprinter
Nomenclature
  • Tarolex
  • UA-8084
  • KL/TGA-3128
  • NSN 5810-17-027-8947
  • Ecolex V
  • Philips Usfa Tarolex (PUT)
Parts
NSN Designator Description
5810-17-027-8947 UA-8084/01 Tarolex key generator
5810-17-027-8989 UA-8928/00 Metal cover (case) for Tarolex
5810-17-032-8855 KL/TGA-3001-C Modified Ecolex IV
? ? Cable between Tarolex and Ecolex
Documentation
  1. Sleutelgenerator KL/TGA-3128, Bediening
    Tarolex User Manual and Technical Description (Dutch).
    1/2 TH 11-957/1. Royal Dutch Army. 11 July 1968. Updated 24 January 1980.

  2. Sleutelgenerator KL/TGA-3128, Technische Beschrijving
    Tarolex Technical Description (Dutch).
    3/5 TH 11-954/1. Royal Dutch Army. undated.
References
  1. Photographs from Philips Usfa
    Crypto Museum Archive.

  2. Philips Usfa, Internal Memo L/5636/AvdP/JG
    23 August 1982, page 3.
Further information
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Crypto Museum. Created: Friday 14 June 2013. Last changed: Friday, 14 June 2024 - 13:30 CET.
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