Fragile Watermarking Using Finite Field Trigonometrical Transforms
This work addresses authentication and tamper detection for digital images, but it appears incremental as it builds on existing transform-based watermarking methods.
The paper tackles the problem of authenticating and detecting alterations in images by introducing a fragile watermarking scheme using finite field cosine and Hartley transforms, resulting in invisible watermarks with tamper location capability and error-free calculation.
Fragile digital watermarking has been applied for authentication and alteration detection in images. Utilizing the cosine and Hartley transforms over finite fields, a new transform domain fragile watermarking scheme is introduced. A watermark is embedded into a host image via a blockwise application of two-dimensional finite field cosine or Hartley transforms. Additionally, the considered finite field transforms are adjusted to be number theoretic transforms, appropriate for error-free calculation. The employed technique can provide invisible fragile watermarking for authentication systems with tamper location capability. It is shown that the choice of the finite field characteristic is pivotal to obtain perceptually invisible watermarked images. It is also shown that the generated watermarked images can be used as publicly available signature data for authentication purposes.