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American Telephone and Telegraph Company
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The American Telephone and Telegraph Company
(AT&T) was at one time
the largest telephone company in the world. Starting life as
Bell Patent Association in 1874, the company enjoyed a monopoly throughout
most of the 20th century. In 1984, after a series of antitrust investigations,
AT&T was split into seven separate companies, some of when were re-merged later.
More...
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AT&T cryptographic products on this website
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In the late 1980s and the early 1990s, AT&T acquired a number of other
companies, some of which were later sold-off again. One such company was
Gretag in Regensdorg (Switzerland) who made link
encryption devices. This company was later sold to IRE.
After AT&T was broken up into separate companies, various divisions
were sold and resold to other companies, which is why the cryptographic
products were later sold by Lucent Technologies and finally by
General Dynamics.
➤ More about AT&T
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In 1987, the US National Security Agency (NSA) developed
the STU-III crypto phone, and allowed several manufacturers
to build it. The 1100-series was AT&T's contribution to the project.
It was introduced in 1992 as the successor to the rather bulky
Security Plus and came in a number of variants.
➤ More information
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The 4100-series was a cut-down version of the STU-III phone (1100),
with NSA Type 4 encryption, that was suitable for multinational
corporations and foreign governments.
➤ More information
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The 3600 series was a small box that could be inserted
between a regular phone and the line, in order to convert it
into a secure voice system. It was an NSA Type 3 product
that was intended for the (national) civil market.
There were several versions, indicated by a prefix and a suffix
to the model number. Some versions of the TSD-3600 (E and S)
contained the famous Clipper Chip.
➤ More information
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In 1991, Swiss crypto manufacturer Gretag
was taken over by AT&T. At the time, Gretag was selling its line
of link encryption systems, mainly for use by banks. For several
years, the Gretag products were sold in the US by AT&T.
The Gretacoder 524 was a link encryption device for serial signals,
with a transfer speed of 64.000 bits per second.
➤ More information
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© Crypto Museum. Created: Wednesday 09 February 2011. Last changed: Friday, 23 February 2018 - 21:39 CET.
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