Cryptographic Technicians

Cryptology—a term derived from the Greek words kryptos (hidden) and logos (word)—has been used since ancient times, perhaps since people first began to write. The desire to maintain secrecy or privacy for some communications led people to develop codes and ciphers; only people who possessed the key to the code would be able to understand the communication. Secret writing methods were used in ancient Greece, Egypt, Mesopotamia, India, and China.

Julius Caesar used a letter substitution method that involved the shifting of the alphabet, so that the letter D, for example, represented the letter A, the letter E represented the letter B, and so on. This method, or cipher, has come to be called the Julius Caesar cipher. The word cipher may refer to the method of encoding a message or to the encoded message itself.

The use of secret writing techniques increased through the Middle Ages. The science of cryptology, however, is generally considered to have been begun in 1510 by Johannes Trithemius of Germany, who produced the first written text on cryptology. Trithemius also devised the first cipher based on a geometric figure, in his case a square, that allowed the alphabet to be shifted several or many times in the same message, making the message more difficult to decode. Cryptology has played an important role in history, especially during times of war.

In 2013, the work of the National Security Agency (NSA) sparked a controversy when a former contractor released classified NSA secrets exposing widespread surveillance of domestic and international communications. While surveillance continues, some members of the public and privacy advocates have expressed serious concerns about the growing levels of surveillance in the United States and in other countries around the world.