Abstract

Digital watermarking technique emerged as a tool for protecting the multimedia data from copyright infringement. In digital watermarking an imperceptible signal is embedded into the host image, which uniquely identifies the ownership. In the proposed algorithms, DNA sequence is used as a digital watermark, as the DNA sequences are unique and difficult to copy. This paper proposes two algorithms namely content based watermark algorithm using DNA sequence (CBDNA) and user specified watermark algorithm using DNA sequence (USDNA). In CBDNA the DNA sequence is generated from the cover data itself whereas in USDNA input data is chosen by the user and DNA sequence is generated based on the input data. These DNA sequences serve as a watermark for the cover data. The quality of the cover image and extracted watermark is measured using peak signal to noise ratio (PSNR) and normalized correlation (NC) respectively. The calculated values are tabulated and it shows that the proposed algorithm is withstanding many attacks, since watermark is available in all the frequency range of cover data.