Content authentication schemes for digital images

Nowadays, there are two approaches for digital image authentication: the digital signature based approach and the watermarking based approach. Goal of both approaches is detection of tampered regions of an image, while tolerate incidental manipulations. In this paper two methods that belong to both approaches are developed and compared from tamper detection capability points of view. The digital signature based scheme uses the relationship between wavelet coefficients of different level of decomposition to construct a structural digital signature (SDS), while the watermarking based scheme embeds semi-fragile watermark using a quantization function in the discrete wavelet domain. Performance analysis is realized and experimental results show advantage and disadvantage of both schemes.