Anyway, it might be logical to jam some suspicious files, but the point of SteCoSteg is to make the file as innocent as possible and jamming all the images of the entire internet is not realistic, for now. Though, if some encryption is used (like AES in CBC mode) jamming may be problematic to recover the message. Plus, it can resist LSB jamming, the message will be modified, but can be recovered without much effort. It combats statistical analysis like LSB enhancement, pixel evaluation, Chi-Square and all sorts of histograms. It follows the Kerckhoffs's principle, meaning that this is white-box type steganography and all the security is not in the secrecy of the algorithm, but in the key, which is in contrast to security by obscurity, commonly used in steganography. The following implementation provides less secure and less universal method, but more practical without significant drawbacks. Also, this variant is one of the (perhaps the) best-one that could exist in steganography because, it uses maximum data space (length) without any special compression or encoding, contrary to the other hiding techniques. However, the variant will produce a result that may draw suspicion, thus unpractical for most cases, regardless the fact that it is truly white-box and can be done in an untrusted environment, without any particular tools. The variant of this technique can be used to achieve theoretic-level security with an arbitrary storage length, by creating customized images with a specific set of colors. Bigger amount of storage is possible to conceal as well, but the more data is to be concealed, less stealthy it will be, thus it is not optimized for big amount of data concealement since, the respective decoy size is needed. This usage requires a highly entropic image (as photo) and relatively small amount of data to store. Just like Vernam cipher and OutGuess, if SteCoSteg is well used, it will be mathematically impossible to extract the concealed information. The technique is to find the pixels that are more entropic than the others, which basically means to find the least used colors and modify them irreversibly. The security is achieved by the determination of what pixel to use as a storage and by applying a one-way function.Īt this point, it does exactly the same thing as OutGuess, but differently. So, SteCoSteg takes a file, decomposes it by bytes, and store these bytes in pixels of an image. The key it-self is just an encoded pixels list that contains the file. To unconceal a file in a PNG image, one must specify this key. Then, it takes a file and hides it in the image, converting it to PNG, by giving a unique key for the file's retrieval. SteCoSteg operates images, JPEGs are used as a decoy. lossy convertion reformating is not supported (yet).Python - main code, version 2 and 3 compatible.SteCoSteg is OutGuess successor and Vernam cipher analog in steganography.
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