INTRODUCTION It is 499 BCE in the ancient Greek city of Miletus The city’s leader Aristagoras is unhappy Aristagoras’s father-in-law Histiaeus used to lead the city But he has been imprisoned by the Persian Empire The empire controls Miletus So Aristagoras must lead the city in Histiaeus’s place Suddenly Aristagoras learns that a secret message has arrived from Histiaeus A slave is brought to Aristagoras To see the message the slave tells him Aristagoras will have to shave the slave’s head City officials shave the slave’s hair As they do letters are revealed Histiaeus has tattooed a message across the slave’s scalp Soon the full message is revealed Revolt Aristagoras nods It is time to take his city back from Persian rule King Darius I top ruled Persia in 499 BCE 4
In ancient Greece and Rome slaves were often tattooed as punishment 5
CHAPTER 1 WHAT IS STEGANOGRAPHY Steganography is the art of hiding messages in plain sight People must know where and how to look if they want to find information hidden using steganography Steganography is closely related to cryptology Cryptology is the science of secret communication It involves creating codes and ciphers that conceal the meaning of secret messages Messages that have been concealed using a code or cipher are called cryptograms Someone who tries to crack a cryptogram knows that it holds secret information The aim of steganography however is to keep someone from knowing that there is a secret to learn In the 1940s a spy used this doll to smuggle tiny secret photographs into Germany 6
This image might look normal However it could contain information hidden using steganography 7
