Improved CRT-based DCT domain watermarking technique with robustness against JPEG compression for digital media authentication

Digital watermarking techniques have been used as one of the means for copyright protection and authentication of multimedia data. Conventional Singular Value Decomposition (SVD)-based and Chinese Remainder Theorem (CRT)-based spatial domain watermark techniques do not perform well under JPEG compression. However, it is seen that the CRT-based watermarking technique in Discrete Cosine Transform (DCT) domain performs well for JPEG compression. In the current paper, we presented an improved CRT-based DCT domain watermarking scheme. This method is shown to be more robust against cropping, tampering, addition of noise and JPEG compression. The existing CRT-based DCT domain technique results in increase in Tamper Assessment Function (TAF) due to the conversion into DCT domain, whereas the proposed method is shown to reduce TAF under DCT conversion.