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Data NL Philips Ecolex X → ← Ecolex IV
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.
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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).
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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, although
the two machines are not interoperable.
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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).
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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.
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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.
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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.
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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.
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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.
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Siemens T-100 teleprinter
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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
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The cable shown in the imge on the right was used to connect Tarolex
to the interface of the modified Ecolex IV.
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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.
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Device Key stream generator Purpose Self-permuting encryption of military teleprinter traffic Name Tarolex 19" Model UA-8084 Designator KL/TGA-3128 NSN 5810-17-027-8947 Based on Philips Usfa TROL (PUT) Manufacturer Philips Usfa Development 1966-1967 Operational 1967-1982 Customer Royal Netherlands Army Predecessor Ecolex IV, TROL Successor Ecolex X Key length 110 bits Interface 5-bit teleprinter Format ITA-2 Power 110, 127, 220V ?AC}, 47-63 Hz Consumption 28W Temperature 0°C to +55°C Storage -30°C to +70°C Humidity ≤ 95% Dimensions 485 × 470 × 265 mm Weight 33 kg Quantity 151
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- Tarolex
- UA-8084
- KL/TGA-3128
- NSN 5810-17-027-8947
- Ecolex V
- Philips Usfa Tarolex (PUT)
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| | Designator | NSN | Description |
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| 1. | UA-8084/01 | 5810-17-027-8947 | Tarolex key generator |
| 2. | UA-8928/00 | 5810-17-027-8989 | Metal cover (case) for Tarolex |
| 3. | KL/TGA-3001-C | 5810-17-032-8855 | Modified Ecolex IV |
| 4. | ? | ? | Cable between Tarolex and Ecolex |
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- Photographs from Philips Usfa
Crypto Museum Archive.
- Philips Usfa, Internal Memo L/5636/AvdP/JG
23 August 1982, page 3.
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© Crypto Museum. Created: Friday 14 June 2013. Last changed: Monday, 24 March 2025 - 08:28 CET.
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