Steganography/watermarking methods strongly depend on the use case and are generally not fit for many scenarios. But if the picture can be found with and without the data embedded, it’s trivial to extract the embedded data.īut if the image is properly encrypted, even if you can tell with certainty that you extracted embedded data from it, you cannot tell if the data is a picture, an audio file, an executable or plaintext without the key. Images with bad lighting or very high ISO are great for that, because the uniform areas will display noticeable noise even without embedding anything. The results will depend entirely on two premises: the original image cannot contain large areas of uniform color, and the image cannot be found online before the embedding. Even if you run statistics on the storage image it’s not possible to tell with a great degree of certainty that something was embedded on it, as the original was full of noise, and properly encrypted data looks very much like noise. Grab a picture with less than ideal lighting conditions as the storage, and encrypt the secret image before embedding. Posted in Software Hacks Tagged images, maths, steganography Post navigation Meanwhile as we’re on the topic, this isn’t the first time Hackaday have touched on steganography. If you’d like a closer look, there’s even some code to play with. We’re guessing that the increased noise in the image data would be detectable through mathematical analysis, but this should be enough to provide some fun. Thus the bits of a smaller bitmap can be placed in the LSB of each byte in a larger one, and the viewer is none the wiser. In short, small changes in colour or brightness across an image are imperceptible to the naked eye but readable from the raw file with no problems. The process relies on the eye’s inability to see small changes at the LSB level to each pixel. We’re sure Hackaday readers have plenty of their own ideas after reading it. It describes the process at a high level that’s easy to understand for non-maths-wizards. It’s a process that works with digital photographs and is the subject of an article by. If you’ve ever read up on the basics of cryptography, you’ll be aware of steganography, the practice of hiding something inside something else.
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