Encryption is the use of some means to disguise or obscure the meaning of a message.
This is normally achieved by transposing or substituting the characters which make up the message. Encryption is accomplished by a method prearranged by the sender and recipient so that the message can be read only by the intended recipient, who alone possesses the key to unravelling its true meaning. 2.2 History of Encryption Ciphers and codes have probably been in use ever since the development of written language. Transpositional codes were used in classical Greece, and Julius Caesar used a simple 4-letter rotation code. Ciphers have increased in complexity throughout history.