A common steganalysis indicator for potential LSB steganography is what pattern in close-color pairs?

• A. Uniform close-color pairs
• B. High frequency of close-color pairs that differ only in the LSB
• C. Very large image dimensions
• D. Low color depth

Answer: (B)

LSB steganography hides data by flipping the least significant bit of pixel color values. Because only that bit is changed, the modified colors come in pairs that are almost identical, differing only by the LSB (a difference of one). A steganalysis signal is a high frequency of these close-color pairs, where neighboring colors differ solely in the LSB, standing out compared with natural images. The other options don’t specifically reflect this targeted LSB-difference pattern, so they aren’t reliable indicators of hidden data.