Asymmetric Cryptography as subset of digital hologram watermarking

In this paper we propose an asymmetric cryptography as subset of digital hologram watermarking, which is able to detect malicious tampering while tolerating some incidental distortions. It is a fragile watermark; in fact the mark is readily altered or destroyed when the host image is modified through a linear or nonlinear transformation. The proposed technique could be applied to Color Images as well as to Gray Scale ones. Using digital hologram watermarking, the embedded mark could be easily recovered by means of a Fourier Transform. Due to this fact the host image can be tampered and watermarked with the same holographic pattern. To avoid this possibility we have introduced an encryption method using an asymmetric Cryptography. The proposed scheme is based on the knowledge of original mark from the Authentication Entity, for applying Image Correlation between this and the extracted one.