Special Issue Article
A New Method for Satellite Image Security Using DWT-DCT Watermarking and AES Encryption
With the large-scale research in space sciences and space technologies, there is a great demand of satellite image security system for providing secure storage and transmission of satellite images. As the demand to protect the sensitive and valuable data from satellites has increased and hence proposed a new method for satellite image security by combining DWT-DCT watermarking and AES encryption. The researches and applications of applying digital watermarking to geo-information data are still very inadequate. Watermarking techniques developed for multimedia data cannot be directly applied to the satellite images because here the analytic integrity of the data, rather than perceptual quality, is of primary importance. Hence an efficient watermarking is necessary for satellite images. To improve performance, combine discrete wavelet transform (DWT) with another equally powerful transform; the discrete cosine transform (DCT). The combined DWT-DCT watermarking algorithm’s imperceptibility was better than the performance of the DWT approach. Modified decision based unsymmetrical trimmed median filter (MDBUTMF) algorithm is proposed for the restoration of satellite images that are highly corrupted by salt and pepper noise. The proposed method is more robust against different kinds of attacks and the watermarked image obtained is invisible. Satellite images have higher requirements in content security: it desires not only the watermarking for copyright protection but also encryption during storage and transmission for preventing information leakage. Hence this paper investigates the security and performance level of joint DWT-DCT watermarking and Advanced Encryption Standard (AES) for satellite imagery. Theoretical analysis can be done by calculating peak signal to noise ratio (PSNR) and mean square error (MSE). The experimental results demonstrate the efficiency of the proposed scheme, which fulfills the strict requirements concerning alterations of satellite images.