Timeline for Algorithm/Technique for Steganography

Current License: CC BY-SA 3.0

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Mar 4, 2013 at 16:44	comment	added	hunter		Of course, there are lots variables, and results are subjective to the image. However, I've created my own steganographic app and modifying the LSB does not result in a discernable change to the image, even on flat-color such as a blue sky. Assume each pixel contains 3 color values, R, G and B. Each value is between 0 and 255. Modifying the LSB might (assuming the value you're encoding is 1 or 0) result in a change of 1. You're not going to notice a change of 1/255, especially when it's only in 1 of the 3 color channels. Of course, I'm talking about visual inspection, not computational.
Mar 4, 2013 at 16:00	comment	added	John Deters		@hunter, I've seen data LSB stegoed into lossless (bitmap) images, and visibility depends entirely on the subject of the picture. The example I gave above of a clear blue sky was of a real example, and the artifacts in it were painfully visible. If you're going to try it, you'll have to figure out which bytes should have LSBs modified. Even then, a picture with LSB modifications has a different statistical profile than an un-stegoed picture, and they are detectable.
Feb 26, 2013 at 0:41	comment	added	hunter		You're right in saying that lossy formats like JPG are not suitable, but PNG is actually a (typically) lossless bitmap format, ideal for steganography - and it's used very commonly on the internet - unlikely to draw attention. The 'static' you refer to would not appear if you're only modifying the LSB. Modifying even the 2nd or 3rd least significant bits would only result in a difference that is difficult to discern with the human eye (depending on the image). Also, it's common to space out encoded information uniformly across an image, so as to be less conspicuous.
Feb 25, 2013 at 23:20	history	answered	John Deters	CC BY-SA 3.0