A telephone scrambler encrypts phone conversations, keeping unauthorized users from tapping into or monitor calls with any success. Scrambling involves the encryption of data, using unique codes that render it possible only for authorized personnel to unscramble transmissions. In order for scrambling technology to work, it is necessary that both authorized participants in a conversation possess a scrambler/descrambler. Scramblers are available on the consumer market, but most of these are vastly inferior to the technology used by operatives of elite U.S. intelligence services.
In a phone scrambling system, information sent over a public switched telephone network, or PSTN, is scrambled. The authentication of the unscrambling device at the receiving end is checked, and when an incoming message is received, it remains inaccessible until a special code or identification number is entered. One consumer system, according to a report in the trade journal Security, uses voice coding technology as a further security measure.
The principle of telephone scrambling is similar to that applied in making a Web site secure so that users can enter financial information without fear that this data will be intercepted. In both cases, sophisticated encryption makes it all but impossible for interlopers to obtain the desired information.
It is a safe bet that decryption technology and techniques available to an upper-echelon intelligence organization such as the National Security Agency, on the other hand, could easily break into even the best civilian systems. Likewise, U.S. intelligence services in hostile environments such as Iraq during the 2003 war have at their disposal telephone scrambling and decryption technology that would make their transmissions virtually impenetrable.
█ FURTHER READING:
Baldauf, Scott. "Where to Find the Perfect Gift for Your 007 Wannabe." Christian Science Monitor. (December 7, 1999): 2.
"How Secure Are Your Phone, Fax, Data Transmission Systems?" Security 34, no. 6 (June 1997): 75–76.
Nolte, Carl. "Spy Store a Boon for Paranoid Public." San Francisco Chronicle. (January 18, 2002): A23.