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The Pierre-sur-Haute military radio station is a French military communications site that has been in use since 1913. The 30-hectare (74-acre) station is located on a hilltop in the Sauvain and Job communes 45.6531°N 3.8084°E.
Vint Hill Farms Station was established during World War II in 1942 by the Army's Signal Intelligence Service (SIS). The 701-acre (284 ha) facility was built because the Army needed a secure location near SIS headquarters in Arlington Hall to serve as a cryptography school and as a refitting station for signal units returning from combat prior to redeployment overseas.
Yellow dots on white paper, produced by color laser printer (enlarged, dot diameter about 0.1 mm) Printer tracking dots, also known as printer steganography, DocuColor tracking dots, yellow dots, secret dots, or a machine identification code (MIC), is a digital watermark which many color laser printers and photocopiers produce on every printed page that identifies the specific device that was ...
Controlled Cryptographic Item (CCI) is a U.S. National Security Agency term for secure telecommunications or information handling equipment, associated cryptographic component or other hardware item which performs a critical communications security (COMSEC) function.
A police code is a brevity code, usually numerical or alphanumerical, used to transmit information between law enforcement over police radio systems in the United States. Examples of police codes include " 10 codes " (such as 10-4 for "okay" or "acknowledged"—sometimes written X4 or X-4), signals, incident codes, response codes , or other ...
A covert listening device, more commonly known as a bug or a wire, is usually a combination of a miniature radio transmitter with a microphone. The use of bugs, called bugging, or wiretapping is a common technique in surveillance , espionage and police investigations.
A secret decoder ring (or secret decoder) is a device that allows one to decode a simple substitution cipher—or to encrypt a message by working in the opposite direction. [ 1 ] As inexpensive toys, secret decoders have often been used as promotional items by retailers, as well as radio and television programs, from the 1930s through to the ...
A protective distribution system (PDS), also called protected distribution system, is a US government term for wireline or fiber-optic telecommunication system that includes terminals and adequate acoustical, electrical, electromagnetic, and physical safeguards to permit its use for the unencrypted transmission of classified information.