In February, USA Today and Wired News reported that bin Laden uses steganography -- the practice of hiding messages within messages -- to communicate covertly with his associates.

Steganography is an ancient practice with advanced applications in the digital age. Electronic messages can be hidden within digital images, audio files, or even other text messages by storing the secret information within inessential lines of code that don't alter the look or sound of the original file. Wired News referred to a paper by Neil F. Johnson of George Mason University that shows an example of two images of William Shakespeare, one with a hidden message and one without.

Bin Laden's use of steganography is yet another reason the US intelligence community is calling for stricter regulations on encryption technology. Dozens of steganography programs are currently available online.

Steganography software

JSteg Shell is a freeware program you can use if you want to try your hand at steganography. It is compatible with Windows 95, Windows 98 and Windows Me. It is not compatible with Windows 2000.

Based on original reporting by David Roos, Web producer for Silicon Spin.