Illegals
The name used by Russia's overseas intelligence agency, the SVR, for its secret agents living in the US.
Legend
The false identities provided to the illegals before they leave Russia, and then built up inside the US.
Deep cover
When the agents are entrenched within their host society for years or decades.
Steganography
From the Greek, meaning "concealed writing", the placing of hidden messages. The modern version involves the encryption of messages concealed within the binary code of digital images on publicly accessible internet sites.
Ad hoc network
Covert communication between a pair of laptop computers temporarily linked to exchange files.
Brush-past meetings
Also known as "flash meetings", where two people secretly pass items as one walks past the other in a public place.
Radiograms
Bursts of coded radio data to the agents' handlers in Moscow.
Drop site
A designated spot at which a small item is left by one agent for another to collect.