During World War II [Wright, 1987; Haynes and Klehr, 1999], the Soviet Union communicated with its legitimate and covert representatives in the United States by
Diplomatic pouches provided security, but communication was slow; it was illegal to encipher messages for transmission by telegraphic cable companies. The Soviet Union was forced to rely on encrypting short-wave radio as a means of secreting their messages.
The Soviet Union operated five communication's channels:
Unlike Japan and Germany, which opted for electromechanical devices, the Soviet Union decided to use the one-time pad, which would provide absolute secrecy if correctly used.
The USSR employed two-part superencipherment (Table 4.9); the first phase used a codebook, a dictionary listing 4-letter groups codes for some set of common (plaintext) phrases. The codebook might have been particular to a specific ...