Distributed Steganography Using CAPTCHA Codes.

The article describes a new distributed steganography protocol that uses CAPTCHA codes as containers for hiding secret information. CAPTCHA codes used for user authentication allow for the identification of human users, but they can also serve as containers for hiding parts of secret information. A special combination of selected parts of the visual CAPTCHA allows trusted users to access selected systems or services, but also allows for the collection of a special set of containers that contain a specific amount of divided secret information. The article also discusses the security and application of such distributed steganography solutions.