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