Throughout history, steganography
has been the means for covert communications. From tattoos on a carrier's
head hidden by hair to urine used as invisible ink, the art of steganography continues to evolve.
Current day techniques use steganography in digital form. Messages can be hidden
in empty spaces found in a file. Other techniques involve modifying the
Least Significant Bit or a digital picture.
The 9/11 attack heightened our awareness of steganography. It is well published that Bin Laden and
his terrorist cells use steganography for
communications. In fact, it was published in USA Today newspaper months
before the actual attack.
Steganography is a huge subject of debate. It continues to thwart
investigators and forensics specialists, because it is very difficult to
detect. To add to the complexity, most messages are encrypted prior to
hiding them in a picture.
On the flipside, it is an incredibly strong
technique for private communications for the military and companies alike.
Hopefully research will allow us to detect
and reveal these terrorist messages, yet also allow the military and
companies to leverage the combination of strong steganographic
and cryptographic algorithms.