![Ky-3](https://upload.wikimedia.org/wikipedia/commons/0/02/Ky-3.jpg)
The KY-3 (TSEC/KY-3) is a secure telephone system developed by the U.S.
National Security Agency
The National Security Agency (NSA) is a national-level intelligence agency of the United States Department of Defense, under the authority of the Director of National Intelligence (DNI). The NSA is responsible for global monitoring, collect ...
in the early 1960s. It was one of the first widely accepted voice voice encryption systems.
The "TSEC" prefix to the model number indicates NSA's Telecommunications Security
nomenclature system.
It was made by the
Bendix Corporation according to specifications of the NSA. According to information on display in 2002 at the NSA's
National Cryptologic Museum
The National Cryptologic Museum (NCM) is an American museum of cryptologic history that is affiliated with the National Security Agency (NSA). The first public museum in the U.S. Intelligence Community, NCM is located in the former Colony Sev ...
, the KY-3 provided high fidelity
secure voice
Secure voice (alternatively secure speech or ciphony) is a term in cryptography for the encryption of voice communication over a range of communication types such as radio, telephone or IP.
History
The implementation of voice encryption dat ...
over special wide-band circuits known as "4-wire dedicated drops", since it used
pulse-code modulation
Pulse-code modulation (PCM) is a method used to digitally represent sampled analog signals. It is the standard form of digital audio in computers, compact discs, digital telephony and other digital audio applications. In a PCM Stream (comp ...
encoding for the audio which gave it "high-quality speech". Its overall high power requirements and physical size limited its "tactical" use but gained popularity among executives, diplomats, military leaders and the intelligence community. More than 2,500 units were produced between 1965 and 1967
and it was one of the first
telecommunication
Telecommunication is the transmission of information by various types of technologies over wire, radio, optical, or other electromagnetic systems. It has its origin in the desire of humans for communication over a distance greater than that fe ...
security devices to use transistors packaged into functional modules. The unit was packaged in a grey
relay rack cabinet. It was The KY-3 was replaced by the
STU-I and
STU-II and remained in use until the late 1980s.
See also
*
STU-III
STU-III (Secure Telephone Unit - third generation) is a family of secure telephones introduced in 1987 by the NSA for use by the United States government, its contractors, and its allies. STU-III desk units look much like typical office telephone ...
*
Secure Terminal Equipment
Secure Terminal Equipment (STE) is the U.S. government's current (), encrypted telephone communications system for wired or "landline" communications. STE is designed to use ISDN telephone lines which offer higher speeds of up to 128 kbit/s ...
*
SCIP
References
{{Cryptography navbox , machines
National Security Agency encryption devices
Secure telephones