Homepage Cyberwar Cybersecurity Cyberspace C-Spionage C-Sabotage Gefährdung Kriminalität Computer Kommunikation mod. Systeme Der Mensch Beratung Bildung Fachberichte Information Kryptologie Emission Verschlüsselung Forschung Begriffe Recht Technik Verschiedenes
.R F I D  - Systeme   Verschlüsselungs- und Chiffriertechnik   Rotorsysteme   Computerkryptologie
STU - III
Ansicht
Information : Crypto Museum Niederlande
Information Crypto Machines Canada
Information
aus Crypto Museum
more information
abhörbar intercept intercepter перехват 截距
STU - III
Entwicklungsbeginn : keine Angaben
Schlüsselsystem : keine Angaben
Arten der Chiffrierverkehre : keine Angaben
kryptologische Festigkeit : keine Angaben
Betriebsart : keine Angaben
Übertragungsart der Information : keine Angaben
Information :
STU-III
Secure Telephone Unit, generation 3

The STU-III is the last of a series of analog secure telephone units, developed by the National Security Agency (NSA) in the United States. STU is the abbreviation of Secure Terminal Unit. The STU-III was introduced in 1987 as the successor to the STU-II. The units were built by various manufacturers, such as Motorola, RCA and AT&T. There are different versions, for desktop use and wall mounting, with a built-in modem for fax and data transmission. It was succeeded in the 1990s by the STE and eventually by the SCIP standard in the 2000s.

The image on the right shows a typical STU-III unit. The one shown here is the top-of-range SECTEL 2500 from Motorola. It has a black case, made of metal and plastic, but it was also available in beige. It is capable of sending voice and data at 2400, 4800 and 9600 baud.

A similar Motorola SECTEL was used in 2001 by former US president George W. Bush to liase with his security advisors just after the 9-11 attacks on the World Trade Center in New York, whilst visiting Emma E. Booker Elementary School in Sarasota (Florida, USA) (see below).
Motorola SECTEL 2500 with CIK

Several hundreds of thousands STU-III phones were produced. They were used in the US and some allied countries. Although the phones have now been discontinued and are gradually being phased out, many remain in service today. STU-III uses NSA Type 1 or Type 2 encryption, allowing conversations at all levels of security classification, up to Top Secret. Special lower grade variants, with Type 3 and Type 4

Despite the secrecy surrounding the KL-7 and its history, the mystery is gradually being unravelled as the NSA releases more and more historical documents and researchers manage to uncover more and more technical details of the machine. As a result, a reaslistic computer simulation of the KL-7 is now available from crypto-historian Dirk Rijmenants in Belgium.