Algorithms for HTML. Stanislav S. Barilnik, Igor V. Minin, Oleg V. Minin. Abstract - Nowadays the Internet is a highly developed communication system. Every day ...
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Adaptation of Text Steganographic Algorithms for HTML Stanislav S. Barilnik, Igor V. Minin, Oleg V. Minin Abstract - Nowadays the Internet is a highly developed communication system. Every day the number of the users of the Internet increases for thousands of people. This system is open for everybody: either a lawabiding and decent person or a quite opposite one. This leads to such problems of the defense of information as copyright and transmission of hidden messages via World Wide Web through open communication channels. This article covers methods, which can help to solve these problems with usage of text steganographic algorithms.
TTSUALLY, BEEN BASED ON PECULIAR-
rities of HTML-language, the information of authorship is indicated on an appropriate page in
three main ways: * directly in the text, usually at the foot of the page; * in the form of the commentaries in the document; * via tag . But all these indications of authorship can be
easily modified and afterwards it is rather problematic to prove the copyright for this or that docu-
ment. Apart from lawful ways it is expedient to use information ways of defense. Algorithmic mechanisms (mainly, steganographic and cryptographic), little by little, will allow to secure access to and transmission of works and supplement lawful protection provided by law and/or contract effective technological defense. They are aimed at resisting threats with the help of technique itself. This phase was well depicted by Charles Clark in his famous phrase, "The answer for the machine is contained in the machine" - it means that critical situation with offense against the rights of authors and publishers in the internet can be solved only with the help of new communication systems. Use of special stealthographic technologies which enable placing within web-document (HTML- codes) "invisible" for unauthorized person messages will help to solve this problem at least
partly [3]. Most of well-known today programs like Steganos for Windows help to hide information in different types of files. Let's have a look at principle of work of such a program on a model of text file. Bits of hidden information are introduced in a form of unprintable symbols. Such symbols are a
"gap" and a "horizontal tabulation". Thus, we can present bits in the form of symbols: "1" - gap', "O" - "horizontal tabulation". Each byte of hidden information is transformed into a succession of these symbols where each symbol corresponds with a bit of hidden byte. For example: Hidden byte - Ox43 = 0100 0011 =>
,
11
where is «Gap>>, -is «Horizontal tabulation>>. Then this succession is placed at the end of the line and becomes "invisible". In this way you can hide one byte of information in a line but it is easily detected. For this it is enough to mark the text or make the text-editor mark unprintable signs (T). Most of programs which enable to hide information in the text work on the same principle. In Fig. 1 one can see the result of the work of program Steganos for windows. Text-editor in the mode of representation of unprintable symbols (T - switching this mode in Microsoft word). > is a "gap", «->> is "horizontal tabulation", « T >> is a line-shift. Thus, editor shows "visibility" of hidden information. =SF -. -4 >OxOD OxOA, i.e. presence of OxOD is . Thus, in every line of a text one can hide one bit and can
Fig. 6. File -result without putting down different endings by casual.
Besides, the program allows disclosing hidden bytes on this algorithm and putting them into a separate file. Such an algorithm in the program covered below is called Mode 2.
COMPARATIVE ANALYSIS OF MODES OF OPERATION
BARILNIK et al.: ADAPTATION OF TEXT STEGANOGRAPHIC
Each mode has its advantages and disadvantages. The first mode and Program Steganos for Windows possesses less degree of concealing than the second one, because it is much easier to detect gaps and horizontal tabulations at the end of the line than different line-shifts. So, the information hidden by algorithm of the second mode is more protected from disclosing. However, as for the number of hidden information then the second mode is worse. For example, to hide the line, "Author: Barilnik Stanislav (c) Novosibirsk March 2007 Program Steganography. All the rights are reserved" which contains 105 symbols; it will require 105 lines in the first mode. In program Steganos for Windows this meaning will take about 20 lines more, as this supplement hides only files and doesn't work with separate lines. So, at first the hidden line has to be saved into a file and only after this it can be hidden.
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information in the second mode. So, this algorithm can be used for copyright protection and transmission of hidden information via open channels of the Internet.
gram in Mode 2.
In Fig. 7 and 8 there are shown block-schemes of the algorithms of the first and second modes.
1gra. /i.
Moud-el.
gram in Mode 1.
At first, Steganos for Windows hides characteristics of the file (title, attributes, etc.) and then its content, i.e. hidden line. Shown below program works with lines, i.e. it hides only hidden lines. Consequently, the size of the container in the first mode and for Program Steganos for Windows will be about 7-10 Kb. In the second mode, the size of the container should be much bigger as only one bit can be hidden in one line in this mode. So, to hide the same line it will require a container 8 times bigger, i.e. 50-80 Kb. Modem Web-sites in the Internet have a quite big size (50-150 Kb), which is enough to hide
DESCRIPTION OF THE PROGRAM The supplement is written in a programming language "Java". The choice of the language is conditioned by the fact that its programs are crossplatformed. It means that supplements are not tied up to the particular operational system. They work so good in Windows as well as in UNIX systems, and, besides, in any other platform where virtual Java machine is fixed. This language is protected from the overfilled buffer, i.e. it is unlikely that during the work the supplement will hover or will lead to a mistake of memory. One of the peculiarities of this language is that it doesn't have any basic unsigned type, i.e. such a variable quantity as byte (type which takes one byte in memory is mainly used in work with files) has maximum meaning 128 (0x80), left range (0x8 1 -OxFF) is used for negative numbers. But it doesn't influence on this program as it works in the 16th system, i.e. a symbol from the table of ASCII codes is used for every 16th meaning of the byte. The program has a simple and intuitively clear interface, it works in a dialog-mode, and so it shouldn't cause any difficulties in usage.
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INTERFACE OF THE PROGRAM Changing modes is done from the menu by pushing "mode": Default mode is Mode 2. Piloting the program is done through two windows. One is for hiding information and the other is for disclosing it.
Fig. 10. Window for piloting disclosing the data.
To the right of these windows there is a panel(board) which shows the web-site where the program hides the information.
CONCLUSIONS These articles dealt on the principles of hiding information in HTML-files. Two new algorithms for hiding information were suggested. Their characteristics were analyzed and main fields of their usage were defined. REFERENCES [1]
[2]
Belyaev A., , access mode:
ml, free.
Kartashov D.V., Chijuhin G.N., , access mode: http://www.pniei.penza.ru/conf/tom4/005/cl.htm, free.
[3]
[4]
N. E. Gerasimov, I. V. Minin, 0. V. Minin, STEALTHOGRAPHIC PROTECTION OF INTELLECTUAL PROPERTY IN WWW DOCUMENTS H Scientific symposium TECHNOMAT & INFOTEL 2007, BULGARIA Tekin V., , - World of PC, XN 11,2004.
