| 1.0 IntroductionSteganography is one of the oldest | | | | operation being unknown to the enemy, but rather |
| arts that people have always wanted to have since | | | | on the choice of a secret key.1.1 BackgroundIn |
| they started communicating with each other, but | | | | recent years there has been an exciting convergence |
| sadly the least researched. Most people study | | | | of information protection technologies and the main |
| steganography either as academic discipline or out of | | | | emphasis is information hiding as oppose to |
| curiosity and I belong to the latter camp. Although | | | | encryption. The two big policy issues of copyright |
| steganography is used in military and commercial | | | | protection and state surveillance motivated this |
| circuits the level of application and understanding is | | | | development. The more information that is placed on |
| very low.The term steganography as well | | | | the Internet or public media, the more the owner of |
| cryptography was derived from the Greek language. | | | | the information need to protect themselves from |
| The prefix crypto comes from the Greek word | | | | theft and abuse. The entertainment industry is |
| kryptos, which means hidden or secret. The suffix | | | | particularly very nervous due to the ease at which |
| graphy was derived from graphia, which means | | | | exact copies of digital music and video can be made. |
| writing. Cryptography is essentially the art of secret | | | | The way forward is to embrace advance technology |
| writing and the goal is to maintain the secrecy of the | | | | to protect investment rather than oppose it. Part of |
| message even if it is visible. Steganography is also a | | | | the solution may be a change in the sale process of |
| form of writing (concealed writing). The Greek word | | | | music and video; one mechanism is copyright marking |
| steganos means unseen or hidden. Steganography is | | | | (hiding notices and serial numbers in a way that would |
| a form of hidden communication, it should not be | | | | be difficult for pirates to remove). Systems and |
| seen as a replacement for cryptography but rather | | | | techniques that can uncover hidden information will |
| as a complement to it. Steganography, although | | | | be useful in computer forensics and digital traffic |
| closely related to cryptography, is different. The goal | | | | analysis. Understanding the limitations of current |
| of cryptography is to conceal the content of a | | | | techniques can help develop more robust techniques. |
| message, while the goal of steganography is to | | | | The principal focus is hiding information or at least |
| conceal the existence of a message. However, these | | | | stopping other people from hiding information.2.0 |
| two techniques can be combined effectively by first | | | | SteganographySteganographic techniques have been |
| encrypting the secret message before embedding in | | | | used since World War I and World War II, Chemicals |
| a cover data. Concealing the transmission of | | | | were developed and used as secret inks that |
| encrypted messages enhances their overall security | | | | become visible when brought in contact with other |
| since outsiders are unaware of the | | | | chemicals. A brief history of steganography would |
| communication.Encrypted data can attract the | | | | give us a valuable background.2.1 HistoryGreek |
| attention of hackers and investigators through its | | | | historian Herodotus recorded the earliest records of |
| mere existence, however if concealed, no attempt | | | | steganography. When Histiaeus had to send a secret |
| would be made to break the code or to obtain the | | | | message to his son-in-law, he shaved the head of a |
| secret key. Steganographic methods primarily use | | | | slave and tattooed a message, he waited till the hair |
| image or audio files to hide encrypted data, such | | | | had grown before dispatching him in order to avoid |
| techniques conceal information in the least significant | | | | detection. Another Greek history was when |
| bits of the carrier medium, which serves as a hiding | | | | Demeratus scraped the wax off tablets and wrote |
| place. It is important that the carrier medium does | | | | messages on the underlying wood he then covered |
| not lose its appearance after the embedding | | | | the wood with wax again to conceal the message. |
| process.Another technique similar to steganography is | | | | The tablets appear to be blank and unused when |
| watermarking, the goal of watermarking is to mark | | | | inspected.Invisible ink has always been a popular |
| an image or sound file to the owner by making | | | | method of steganography. Ancient Romans wrote |
| elusive modifications to the file. These modifications | | | | between lines using invisible inks made from |
| should not be noticeable but rather, very robust; | | | | substances like milk, urine and fruit juices. When it is |
| nobody should be able to remove an existing mark or | | | | heated, the invisible ink would darken and become |
| mark an already marked file as belonging to him. This | | | | legible.Gaspari Schotti wrote the earliest book on |
| technique is of great interest to the entertainment | | | | steganography in 1665 called Steganographica. A |
| industry because it gives an efficient way to | | | | major development in the field occurred in 1883 with |
| determine if a file was illegally downloaded from the | | | | the publication of Auguste Kerckhoffs cryptographie |
| web or rightfully purchased.A good steganography | | | | militaire. Although the work was mostly on |
| system should fulfil the same requirements posed by | | | | cryptography, it provides valuable principle in the |
| the Kerckhoff principle in cryptography that security | | | | design of new steganographic systems [SEL03].2. |
| of a system should not rely on the on its method of | | | | |