Задача по теме: "Грамматика и Лексика"

Cryptography  

25. The first form of cryptography was actually the simple writing of a message. Do you know why? Because most people were unable to read or write. In fact, the very word cryptography comes from the Greek words ’kryptos’, which mean ’hidden’, and ’graphein’, which means ’writing’. Cryptography, by its very nature, implies secrecy and _____________ (DIRECTNESS). 

26. Early cryptography included transforming messages into _____________ (READABLE) figures to protect the content of a message while it was carried from one correspondent to another.  

27. Nowadays, cryptography has evolved ____________ (GREAT) and today it includes such things as digital signatures, authentification of a sender or receiver and many more.

28. People wanted to conceal messages since they moved out of caves and started living in groups. The earliest forms of cryptography were found in the cradle of ________________ (CIVILIZE), Egypt, Greece and Rome. 

29. The Greeks, for example, wrapped a tape around a stick, and then wrote the message on the wound tape. Unwinding the tape made the writing ____________ (MEANING). The receiver of the message had a stick of the same diameter and used it to decipher the message.