|
The science of communicating in a way
which hides the existence of the communication. Unlike codes, which render
communications unreadable but still potentially interceptable, steganography
(from a Greek phrase meaning covered writing) relies on hiding messages
where they would not be expected.
Steganography tools such as
invisible inks and microdots have long been used by espionage agencies. Now
digital versions of these tools are creeping into the internet culture,
Owners of digital images, for example, can encode a watermark within jpeg
or gif files to track pirate copies of their property. A casual
observer will see nothing but the picture itself, but the creators of the
watermark can detect its pattern. Such techniques are being extended to
audio files, and form an important part of the sdmi anti-piracy
initiative. Encrypted music samples can be played normally by appropriate
hardware or software without the listener being aware of alterations to the
signal. In Sdmi's watermarking technology proved that this was not the case,
a discovery that prompted legal action to prevent them publishing the
details of their work. |
