Devil's Night

“Where shall I begin, please your Majesty?”

“Begin at the beginning”, the King said gravely, “and go on till you come to the end; then stop.”

Alice’s Adventure in Wonderland; Lewis Caroll

Introduction

For thousands of years, kings, queens and generals have relied on efficient communication in order to govern their countries and command their armies. At the same time, they have all aware of the consequence of their messages falling into the wrong hands, revealing precious secrets to rival nations and betraying vital information to opposing forces. It was the threat of enemy interception that motivated the development of codes and cyphers: techniques for disguising a message so that only the intended recipient can read it.

The Evolution of Secret Writing

Some of the earliest account of secret writing date back to Herodotus, ‘the father of history’. He chronicled the conflicts between Greece and Persian in the fifth century B.C, According to Herodotus, it was the art of secret writing that save Greece from being conquered by Xerxes, King of Kings, the despotic leader of the Persians.

Occasionally, the Persian’s military build-up had been viewed by Demaratus, a Greek who had been expelled from his homeland and who lived in Persian city of Sua. Despite of being exiled he still felt some loyalty to Greece, so he decided to send a message to ware the Spartans of Xerxe’s invasion plan. He scrapped the wax off from a pair of wooden folding tablets, writing underneath his message and then covering the message over with wax again. His method reached its destination successfully.

Demaratus’ strategy for secret communication relied on simply hiding the message. Herodotus also recounted another incident in which concealment was sufficient to secure the safe passage of a message. A people shaved the head of his messenger, wrote the message on his scalp, and then waited for the hair to regrow. This was clearly a period of history that tolerated a certain lack of urgency. This messenger, apparently carrying nothing contentious, could travel without being harassed. Upon arriving at his destination he then shaved his head and pointed it at the intended recipient.

Secret communication achieved by hiding the existence of a message is known as steganography, derived from the Greek words steganos, meaning ‘covered’, and graphein, meaning ‘to write’. In the two thousand years since Herodutus, various forms of stenganography have been used to throughout the world. In China, people wrote message on a fine silk then scrunched into a tiny ball covered by wax. The messenger would then swallowed the tiny ball. In the fifteenth century, the Italian scientist Giovanmi Porta described how to conceal a message within a hard-boiled egg by marking an ink form a mixture of one ounce of alum and a pint of vinegar. As far back to 1st century, people found that milk from thithymallus plant can somehow used as ‘invisible ink’.

The longevity of steganography illustrates that it certainly offers a modicum of security. but it suffers from a fundamental weakness. If the messenger is searched, torched or bribed, then the content of the secret communication are revealed at once.

Hence, in parallel with the development of steganography, there was the evolution of CRYPTOGRAHY