A number of researchers, funded by the NSA and law enforcement agencies,
are working on the problem of
detecting steganography, or determining whether an innocuous
file contains a hidden message. According to these researchers, most steganographic systems out there are hopelessly inadequate and easily revealed.
"What we've done is gone out, using Web spiders, and downloaded pictures from the Web and run the tool against them."
Steganography, Gordon said, primarily turns up on hacker sites. But he and his associates also found instances of steganography on heavily traveled commercial sites such as Amazon and eBay.
First-generation stego programs typically embedded information in the least significant bits that represented the pixels of an image. But images, especially compressed ones, often have predictable patterns that are disrupted when an image is inserted.