The Greeks

The Greeks get credit for using steganography in a few inventive ways. Herodotus, who documented the conflict between Persia and Greece in the fifth century B.C., felt that the art of secret writing saved Greece from Xerxes, the tyrant king of Persia. The trouble, and the use of steganography, began after Xerxes began building his new capital at the city of Persepolis. Gifts began arriving from all over the empire with the exceptions of Sparta and Athens. This insult to Xerxes brought the long-running feud between Greece and Persia to a head. Deciding to teach the Greeks a lesson, Xerxes spent the next five years amassing the largest fighting force in history, and in 480 B.C. he was ready to launch his surprise attack.

Fortunately for the Greeks, the Persian military buildup had been witnessed by Demaratus. Demaratus was a banished Greek who happened to live in the Persian city of Susa. Demaratus, who still felt a loyalty to Greece in spite of his expulsion, decided to warn the Spartans of Xerxes' plans to invade Greece. Naturally, the difficulty was getting the message to the Spartans without it being intercepted by the Persians. Herodotus wrote:

As the danger of discovery was great, there was only one way in which he could contrive to get the message through: This was by scraping the wax off a pair of wooden folding tablets, writing on the wood underneath what Xerxes intended to do, and then covering the message over with wax again. In this way the tablets, being apparently blank, would cause no trouble with the guards along the road. When the message reached its destination, no one was able to guess the secret, until, as I understand, Cleomenes' daughter Gorgo, who was the wife of Leonides, divined and told the others that if they scraped the wax off, they would find something written on the wood underneath. This was done; the message was revealed and read, and afterwards passed on to the other Greeks.

This warning to the defenseless Greeks gave them time to arm themselves. The profits of a silver mine, which was owned by the state, were distributed to the citizens; these profits were now given to the navy for the construction of 200 warships. With the element of surprise lost, the Persian fleet sailed into the Bay of Salamis near Athens to face a very prepared Greek navy. The Greeks, knowing that their warships were smaller, fewer, and would not last long on the open sea, lured the Persian fleet into the harbor where they had the advantage of maneuverability in a confined space. The Persians, realizing this, attempted a retreat but were blown into the bay by a change of winds. At this point the Greeks launched a full attack and did significant damage to the Persian fleet in less than a day.

In "The Histories," Herodotus documented another instance where steganography was used. A Greek named Histaiaeus wanted to encourage Aristagoras of Miletus to revolt against the Persian king, and did so in a rather inventive way. In order to pass these instructions securely, Histaiaeus shaved the head of his messenger, wrote the message on his bare scalp, and then waited for the hair to grow back. While this certainly is not the quickest method of communication, it was very effective because the messenger was able to pass guard inspections without harassment because he was carrying nothing suspicious. When the messenger reached his destination and the intended recipient, his head was shaved and the message read. Similar to this was the instance where a rabbit's belly was shaved, the message written, and the hair allowed to grow back, making the rabbit the stego-medium rather than the person.

Another, more subtle mention of steganography was found in Homer's Iliad. As the story goes, Bellerophon was being enticed by Anteia, who happened to be the King's wife. When Bellerophon refused her advances, Anteia cried rape. The King ordered Bellerophon to go to Lycia and to carry an enciphered message with him to their King. The message to the King happened to contain Bellerophon's execution order. On reading the enciphered message, the King decided not to execute him and instead married him off to his own daughter.