SELF RECOVERY AUTHENTICATION OF IMAGES IN THE DWT DOMAIN

The interest for multimedia contents authentication has recently increased. In particular watermarking-based authentication schemes seem to be offering some advantages with respect to classical cryptography tools (e.g. real content authentication, localization of manipulations, storage format independence, transparency to common signal processing, etc.). In this paper a simple and secure self recovery authentication algorithm which hides an image digest into some DWT subbands of the to be authenticated image is presented. This technique has been designed for video surveillance and/or remote sensing applications. The main goal of this approach is to detect possible malevolent object manipulations undergone by the image (object replacing and/or deletion) by means of a self recovery processing. This valuable characteristic has to be maintained also when an image is processed through an usual and friendly transformation like JPEG compression. Particular care is given to make the scheme robust against innocuous manipulations, and secure against forgery attempts. Experimental results are presented that demonstrate the good performance of the proposed system.