Discrete cosine transform and hash functions toward implementing a (robust-fragile) watermarking scheme

Abstract

This paper proposes a blind multi-watermarking scheme based on designing two back-to-back encoders. The first encoder is implemented to embed a robust watermark into remote sensing imagery by applying a Discrete Cosine Transform (DCT) approach. Such watermark is used in many applications to protect the copyright of the image. However, the second encoder embeds a fragile watermark using 'SHA-1' hash function. The purpose behind embedding a fragile watermark is to prove the authenticity of the image (i.e. tamper-proof). Thus, the proposed technique was developed as a result of new challenges with piracy of remote sensing imagery ownership. This led researchers to look for different means to secure the ownership of satellite imagery and prevent the illegal use of these resources. Therefore, Emirates Institution for Advanced Science and Technology (EIAST) proposed utilizing existing data security concept by embedding a digital signature, "watermark", into DubaiSat-1 satellite imagery. In this study, DubaiSat-1 images with 2.5 meter resolution are used as a cover and a colored EIAST logo is used as a watermark. In order to evaluate the robustness of the proposed technique, a couple of attacks are applied such as JPEG compression, rotation and synchronization attacks. Furthermore, tampering attacks are applied to prove image authenticity. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/25/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx Proc. of SPIE Vol. 8895 889504-4 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 08/25/2015 Terms of Use: http://spiedigitallibrary.org/ss/TermsOfUse.aspx

A New Digital Image Steganography Approach Based on The Galois Field GF(pm) Using Graph and Auto

“…Through experimental results, we see that the efficiency (ER = 0.86 bpp, the average value of PSNR is 55.84 dB) of the near optimal data hiding scheme (2,9,8) for gray images with q color = 3 is indeed better than the efficiency of the HCIH scheme (ER = 0.75 bpp, the average value of PSNR is 46.77 dB) in [29]. We can choose suitable values of ER to achieve acceptable quality of the stego images by applying the near optimal data hiding scheme (2,9,8) for palette images with q color = 3 and the optimal data hiding scheme (1, 2 1, ) n n − for palette images with q color = 1.…”

“…The experimental results reveal that the efficiency in embedding capacity and visual quality of the near optimal data hiding scheme (2,9,8) for gray images with = 3 color q is indeed better than the efficiency of the HCIH scheme [29]. The embedding and extracting time of our approach are faster than that of the Chang et al's approach [7].…”

“…For the near optimal data hiding scheme (2,9,8) log p   bits in an image (Proposition 3.24 and Security analysis (3.27)). In Subsection 3.3, we prove that there exist the near optimal data hiding scheme (2,9,8) (Theorem 3.27 and Security analyses (3.45), (3.46)) and the optimal data hiding scheme (1,5,4) (Corollary 3.28 and Security analyses (3.47), (3.48)) for gray and palette images with = 3.…”

“…Based on the purpose of the application, data hiding is generally divided into steganography that hide the existence of data to protect the embedded data and watermarking that protect the copyright ownership and authentication of the digital media carrying the embedded data. Depend on the type of digital media there are many types of steganography, for example image, audio and video steganography [2,3,8,16,17,21,22,27]. This work only focuses on steganography in digital images in spatial domain.…”

“…for binary, gray and palette images with = 1, color q where n is a positive integer, the near optimal data hiding scheme (2,9,8) for gray and palette images with = 3 color q and the optimal data hiding scheme (1,5,4) for gray and palette images with = 3.…”