DATA CONCEALING DEVICE, CONCEALED DATA EXTRACTION DEVICE, DATA CONCEALING METHOD, CONCEALED DATA EXTRACTION METHOD, AND PROGRAM FOR THEM

摘要

PPROBLEM TO BE SOLVED: To provide a data concealing device capable of enhancing the security of concealed information embedded in an image. PSOLUTION: The data concealing device embeds a concealing image 720 to each least significant bit of a medium image 710 and references a key image to apply prediction coding to a medium image 710' to which the concealing image 720 is embedded. The key image is an image to each least significant bit of which a noise corresponding to a password is arranged, and each least significant bit only of the medium image 710' is scrambled. Thus, although a medium image 710" closely resembling the original medium image 710' is generated when coded data are decoded without referencing the key image, each least significant bit of the medium image 710" indicates the scrambled concealing image 720. PCOPYRIGHT: (C)2006,JPO&NCIPI