The necessity to exchange top secret information between the parties has always been and will always be an important question. However with time means of communication become more sophisticated. The task of reliable information protection from unauthorized access is one of the oldest and not resolved problems. Ways and methods to hide secret messages known since ancient times. One of the ways of transmission of hidden messages is steganography, which literally means «a hidden letter» [1].

Steganography - from the Greek steganos (secret) and graphy (record), literally means "cryptogram". Methods of steganography might have appeared earlier than the writing itself (initially conventional signs and symbols were used).

Steganography has been known since the time of Herodotus. In ancient Greece a message was written with sharp sticks at the plate, coated with wax. In one of the stories Demerat wanted to send a secret message to Sparta about the threat of attacks by Xerxes. Then he took wax from boards, wrote a message directly on the tree, then re-covered it with wax. As a result, the board looked unused and passed guards inspection without any problems. Another, rather unexpected way to conceal information or symbols was a tattoo on the head of a shaved messenger. When in the V century BC tyrant Gystius, under the supervision of the king Darius at Susa, had to send a secret message to his relative in the Anatolian city of Miletus, he shaved his slave, and tattooed a message on his head. When the hair grew back, the slave was sent to deliver the message. Thus Herodotus described one of the first cases of the ancient of steganography - the art of hidden messages.

Later to protect the information more effective methods of encryption and cryptography were used. Steganography differs from cryptography in the fact that cryptography can hide the message content and steganography can hide the very existence of the message.

Computer technologies have given new impulse to the development and improvement of steganography. Thus a new direction in the field of information security - computer steganography – has appeared.

Computer steganography is concealing of messages or files in another message or file. For example, steganography can hide the audio or video file in some other information or even large graphic files.

The fight against terrorism and the prosecution of the perpetrators of the terrorist attack of 11 September 2001 drew particular attention to steganography. Some experts believe that the terrorist organization «Al-Qaeda» used the Internet to plan attacks. And steganography helped to preserve the confidentiality of their criminal intentions.

Osama bin Laden and other terrorists used software to create steganographic messages long before the 11 September tragedy, when their goal was the World Trade Center. The article in the newspaper USA Today, published 5 February 2001, informs an official statement of U.S. and foreign government officials that "Bin Laden, accused of organizing bombings of two American embassies in East Africa, as well as other terrorists hide photographs and maps of the identified objectives together with appropriate instructions to their colleagues in the sports chat rooms, on pornographic websites and other resources of the Internet."

Identify hidden messages using steganography is a serious technical challenge for law enforcement officers, thus trying to track down terrorists. During formation of the state budget for fiscal year 2003 the Federal Bureau of Investigation (FBI) made the request to increase funding for the study of new technologies used by terrorists. Many federal agents lack the technical experience needed to detect the use of steganography. This requires not only additional training, but also provides additional funds for the implementation and support of the electronic surveillance of terrorist communications on the Web [2].

The process of steganography can be divided into several stages.

1. Selecting the information file.

The first step in the process of steganography is to select the file you want to hide. It is also called the information file.

2. The choice of container file.

The second step in the process of steganography is to select a file that is used for hiding information. It is also called the container file. In the majority of known steganography programs it is said that for concealment of information the memory container file should be about eight times the amount of memory of the information file. Therefore, in order to hide the file size of 710KB, you will need to schedule volume of 5600KB.

3. Choosing steganographic program.

4. Encoding the file.

Once the information file, the file container and software for steganography are selected, it is necessary to protect the new file with a password.

5. Sending hidden messages via e-mail and its decoding.

The fifth and last stage in the process of steganography is sending of a hidden file via e-mail and subsequent decoding.

On the Internet you can find a large number of paid and free steganographic programs. What is the probability of using one of these, or any other in criminal purposes? What role will the process of steganography perform in the world of cybercrime?

The degree of easiness and complexity of the process was analyzed in the Research Center of computer crime. The actual process of concealment of one file in another is relatively uncomplicated. Video compression, increasing the image, analysis of programs on steganography is easy even for an unprepared user. Unfortunately, the methods of computer steganography are already being used for criminal purposes. While steganography can help in solving the problems of protection of confidential information, for criminals this process is a means of planning and concealment of the crimes [3].

Analysis of trends in the development of computer steganography shows that in the future the interest in the development of methods will be increasing more and more. Prerequisites for this are already formed today. In particular, it is well known that the problem of information security is constantly growing, and stimulates the search of new methods of information protection. On the other hand, rapid development of information technology provides the opportunity to implement these new methods of protection. And, of course, a strong catalyst in this process is the cascade development of the Internet, including producing such outstanding controversial issues as copyright protection, protection of the rights to privacy, organization of e-commerce, computer crime and cyberterrorism.

Literature

1. Тигулев Максим. Стеганозавр или тайнопись на компьютере.

2. http://st.ess.ru/publications/articles/steganos/steganos.htm

3. Privacy Guide: Steganography. http://www.all-nettools.com/privacy/stegano.htm

© Ларионова К.Е. 2009