The large size of the container. To hide a more or less large stehopovidomlennya without significan

Steganography - hide the fact of transferring information. Stehopovidomlennya - message (information), the assignment that you want to hide. Container - information that includes box auto secret information, hides her confidence. box auto Steganographic algorithm - an algorithm which hides stehopovidomlennya in konteyneri.Abo finds message in a container. Stehanostiykist -
Perhaps many are surprised to learn that steganography is older than cryptography (encryption). The word steganography comes from the Greek steganos (secret) and graphy (record). Ukrainian Best Bet: cryptography. People engaged characteristically - taynopystsi. The first written box auto mention of steganography date from the V century. BC Steganography been using the ancient Sumerians and Elina. Sumerians cuneiform clay tablets covered another layer of clay which did not have a secret account. box auto In the "History" of Herodotus mentions a method of steganography when the message nanosylosya Shaved head on a slave. When he zarostav, it sent to the recipient. One of its fertilizer and read the message.
Distortion container for large amounts stehopovidomlennya. If the container is too small (or in any other of its characteristics), its original form is distorted. In the case of the picture appears box auto a lot of noise, distorted image.
The large size of the container. To hide a more or less large stehopovidomlennya without significant distortion of container and container to choose more. It can carry a variety of problems. For example, if you want to pass extra large message, and the size of the container should be many times (hundreds, maybe thousands) of times the hidden message. This in turn could threaten stehanostiykosti, as the likely opponent will be in the first place to check the big picture. Although it is possible to beat and to their advantage by sending many large files. So the enemy will be loaded box auto and empty job analysis.
Key. I'll start by saying that nadumavsya create steganographic box auto bend to the presence of a key. My first thought on related key and steganography was that the key is changed irregularly next pixel coordinates box auto (if image), which will contain the following pieces of information. But then I thought about something else ... If the coordinates that match the following information will form part of the key? That no person box auto enters a key and algorithm gives key? I immediately sat down for implementation.
I will make a small remark that in the course of the article will describe box auto the algorithm theoretically with reference to my realization of the web. One reason: to cover the part of the audience and that is not a programmer. But at the end of the article will give the source code of my programs.
At first I thought that the yield on the two coordinates x and y axes. But having three sets of colors in RGB, you need a third axis z, which is a value from 0 to 2. "The extra coordinate - another key value" - thought I did as shown in the illustration.
As in previous published Habré, the program I would like to make one of the color values corresponded to the value of the symbol table in ASCII. I believe that this container can put more information later as it turned back and for other reasons. But at the same time using only ASCII is for illustrative purposes only. In more complex algorithms need a different approach.
Enter the URL of an image and a message. The result is the key. You can leave the same image URL, enter the key and get the output stehopovidomlennya. Thus, the container does not change! So to detect it from outside influences stehoalhorytmiv impossible, since they were not!
At first, I was worried about the large size of the key. They are larger than most stehopovidomlennya. But squeezing key any longer embarrass me archiver key size. The key word, and therefore even if the key is ~ 60kb, the compression of 500 byte (archiving zip).
Second, as the key the user comes up, and it gives an algorithm that turns out that for each new transfer information to transfer the password, which is bad form in steganography. But I subsequently saw more pluses than minuses.
First. Despite the fact that the algorithm produces keys - they can use infinite number of times, limited box auto only by fear of exposure. It's enough to replace container box auto to another so that each time at given coordinates proved another message. This can be done by any method convenient for the user: touch with free access image or create a picture of myself. If the container is text, you can take a similar texts from sharing or write it yourself. Consider just one innocent blog can be simultaneously a source of secret information. Each illustration, each section (even regular SEO-text) may contain a key for a secret message!
Second. box auto For the same subject in a given image can be countless keys