Computer Security and Cryptography

4.7 VENONA

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 pouch delivered by a courier,
• Commercial cables, and
• Short-wave radio.

Figure 4.4 Graph of normalized κ-values for cipherEx4.1.

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:

1. GRU – Soviet Army General Staff Intelligence Directorate,
2. Naval GRU – Soviet Naval Intelligence,
3. Diplomatic – Embassy and Consular business,
4. Trade traffic – lend lease, The Amtorg Trading Corporation Stands for American Trading Organization (AMTORG), Soviet Government Purchasing Commission, and
5. KGB – Soviet espionage; headquarters in Moscow, residencies abroad.

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 ...