There's a known legit (non-covert) use of digital watermarking in Epson PhotoPC 3000Z and the Kodak DC-290: http://en.wikipedia.org/wiki/Digital_watermarking#Se

There's a known legit (non-covert) use of digital watermarking in Epson PhotoPC 3000Z and the Kodak DC-290: http://en.wikipedia.org/wiki/Digital_watermarking#Secure_digital_camera http://en.wikipedia.org/wiki/Digital_watermarking#Secure_dig... I don't know about covert embedding, but as it's possible, I won't be surprised if it really exists.