CRYPT Seminar

Title: “Scalable Watermarking for Image Authentication”

Speaker:  Angela Piper (University of Wollongong)

Day: Tuesday 15 September 2009
Location: Building 3. Common Staff Room
Time: 13.30-14.30

Abstract: Semi-Fragile watermarks allow the authentication of images by detecting and locating tampered regions while remaining largely unaffected by `allowed' changes, such as compression. Scalable compression allows a single compressed image to be decompressed to produce a variety of images, which have been scaled to suit the display or bandwidth requirements of the user. However, scalable compression causes a breakdown in the assumption used by most semi-fragile watermarks. In this talk, we discuss what goes wrong when semi-fragile watermarks are applied to scalably compressed images and explain the design features of a scalable watermark for JPEG2000 images that solves this problem.