Intelligence: How Naughty Naked Women Serve ISIL, Hiding on the Internet in Plain View, by James Dunnigan.

Since September 11, 2001 the United States has been increasingly successful in capturing documents from Islamic terrorist groups. …

Another problem, that is less talked about openly, is the enormous amount of pornography found on Islamic terrorist computers and the potential problem with the possibility that some of it may contain hidden messages. This is called steganography (hide encrypted text messages in digital … images). Steganography has been around for a long time but only became really practical with the arrival of cheap and powerful PCs.

Inexpensive commercial steganography software began to appear in 2001. These programs, like Camera/Shy in 2002, were basically very easy to use steganography tools that allowed any PC user to hide encrypted text messages in a digital image. Camera/Shy was created to make it easier for people to safely communicate if they lived in nations that censored and monitored the Internet.

Camera/Shy was freeware (given away) and terrorists and criminal organizations began using it. That did not work out as intended because other software firms soon created commercial software (for police and intelligence agencies) that would quickly identify images that had messages inserted by Camera/Shy. This led to a software arms race with new and improved software that worked like Camera/Shy but was harder to detect and decrypt.