![]() ![]() ![]() JPEG images are used on the Internet because of theircompression quality, which does not degrade the image.What is steganalysis?Steganalysis is the discovery of the existence of hidden information therefore,like cryptography and cryptanalysis, the goal of steganalysis is to discover hiddeninformation and to break the security of its carriers. Thesemethods will allow more hidden information (about 30 percent the size of thecarrier) in a carrier file. Thisprocess makes it difficult for visual analysis attacks against the JPEG images.These two methods hide information in more areas of the cover and maymanipulate image properties such as luminance or the color palette. Theimage formats used in these steganography methods cannot be lost and theinformation can be rearranged or recovered.Key fingerprint = AF19 FA27 2F94 998D FDB5 DE3D F8B5 06E4 A169 4E46The transform domain tools include those groups that manage algorithms andimage transforms such as Discrete Cosine Transformation (DCT).The DCT is a technique used to compress JPEG, MJPEG and MPEG in whichpixel values are converted to frequency values for further processing. The tools used in this group are StegoDos, S-Tools, Mandelsteg, EzStego, Hide and Seek (versions 4.1 through 1.0 forWindows 95), Hide4PGP, Jpeg-Jsteg, White Noise Storm, and Steganos. #OUTGUESS STEGDETECT FULL#Tools used to hide information © SANS Institute 2003, Author retains full rightsThere are two possible groups of steganographic tools: the image domain andthe transform domain.Image domain tools include bit-wise methods that apply least significant bit (LSB)insertion and noise manipulation. It can also be used to protectprivate communications where the use of the cryptography is normally notallowed or would raise suspicion.There are also at least two techniques that are part of steganography.Watermarking:- Protects copyright owners of digital documents by hiding a signature in the information in a way that even a modified part of the document conserves the signature.- Prevents discovery by marking in a hidden and unique way every copy of a confidential document.Cover channel:- Allows people to communicate secretely by establishing a secret communication protocol.- Allows non-authorized communication through authorized communication of aKeyfifrienwgearpll.rint = AF19 FA27 2F94 998D FDB5 DE3D F8B5 06E4 A169 4E46© SANS Institute 2003, As part of the Information Security Reading Room. It can be used to communicate with complete freedom evenunder conditions that are censured or monitored. #OUTGUESS STEGDETECT PASSWORD#Another obvious wayis to obtain the password or decryption key from the owner.Why is steganography used?There are many reasons why steganography is used, and it is often used insignificant fields. A drawback to cryptography is that there are many ways toKreetyriefivnegertphriisnt e=nAcFry1p9teFdA2i7nf2oFr9m4a9ti9o8nD oFnDcBe5 Dit Eh3aDsF8bBe5en06Edi4scAo1v6e9re4dE.46The mostobvious example is by knowing about its existence, investigators can apply themany softwares available to decrypt the hidden information. A decryption key or password is needed to retrievethe information. Cryptography enciphers or garblesfiles to hide the information. For example, some photo agencies will use steganography to createdigital “watermarks” of their pictures to protect their trademark.Steganography is different from cryptography. But, of course, thereare many other ways that steganography is being used by people with harmlessmotives. According to experts, thearticle lacked technical information to prove these claims. An article in USA Today claimed that terrorist groups are usingsteganography to communicate without being detected. Therefore, © SANS Institute 2003, Author retains full rightsan image posted on the Internet could contain a secret message and avoidsuspicion. Most people would probably detect no loss in the quality of the image. DBst5eDgEo3kDeyF=8Bs5te0g6oE-4mAe1d6i9um4E© SANS Institute 2003, As part of the Information Security Reading Room. ![]()
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