The use of codes and ciphers to make a message secret.
The CIA glossary defines encryption as the creation of secret messages using codes and ciphers. The reverse operation, carried out by the authorised recipient, is decryption; reading a message without knowing the key is cryptanalysis.1
A historical example: according to the US Department of Energy, Soviet cables from the Second World War, enciphered with one-time pads, were partly read under the VENONA programme. From 1948 the FBI supported it, and those unmasked between 1948 and 1951 included Klaus Fuchs and Julius and Ethel Rosenberg. The programme was closed on 1 October 1980 and declassified in 1995.2
Sources
- CIA, Spy Speak Glossary
- US Department of Energy, Office of History and Heritage Resources, The Manhattan Project: Venona
Checked: 4 November 2026