Since the birth of writing, there has also been the need for secrecy. The story of codes is the story of the brilliant men and women who used mathematics, linguistics, machines, computers, gut instinct, logic and detective work to encrypt and break these secret messages. The series explains how Mary Queen of Scots was trapped by her own cipher; how the cracking of the ‘unbreakable’ Vigenère code remained a Victorian secret, hushed up by the British government; how the well-timed cracking of a single encoded telegram altered the course of World War One, and how the mysteries of the Rosetta Stone were revealed, resulting in the decipherment of Egyptian hieroglyphs. The series also investigates present day concerns about privacy on the Internet and the invention of so-called public-key cryptography.