The authenticity of the watermarked images under various incidental noise is considered in this paper. The watermark is generated using from the content invariant properties of the image and securely embedded in the selected higher textured blocks of the DCT transform of the image to make them robust to jpeg compression and incidental distortions. Response of the authenticator to watermarked images subject to various incidental attacks and compression is evaluated to test the suitability of the scheme to achieve selective authentication.

1. F. Namazi, M. R. Karami, and S. B. Ramazannia, "Block-based Adaptive Image Watermarking Scheme using Visual Perception Model in DCT Domain," Int. J. Comput. Appl. , vol. 41, no. 4, pp. 41–45, Mar. 2012.
2. F. Zhang, W. Liu, W. Lin, S. Member, and K. N. Ngan, "Spread Spectrum Image Watermarking Based on Perceptual Quality Metric," IEEE Trans. IMAGE Process. , vol. 20, no. 11, pp. 3207–3218, 2011.
3. N. Memon, P. W. Wong, and S. Member, "A Buyer – Seller Watermarking Protocol," IEEE Trans. IMAGE Process. , vol. 10, no. 4, pp. 643–649, 2001.
4. C. I. Podilchuk and E. J. Delp, "Digital WM?: Algoritms and applications," IEEE Signal Process. Mag. , no. July, pp. 33–46, 2001.
5. R. S. Alomari and A. Al-jaber, "A Fragile Watermarking Algorithm for Content Authentication," Int. J. Comput. Inf. Sci. Vol. 2,, vol. 2, no. 1, pp. 27–37, 2004.
6. S. Garg, "An Efficient Method for Digital Image Watermarking Based on PN Sequences," Int. J. Comput. Sci. Eng. , vol. 4, no. 09, pp. 1550–1561, 2012.
7. A. Masmoudi, M. S. Bouhlel, and W. Puech, "A New Image Cryptosystem based on Cahotic Map and Continued Fractions," pp. 1504–1508, 2010.
8. A. Masmoudi, "An Efficient PRBG Based on Chaotic Map and Engel Continued Fractions," J. Softw. Eng. Appl. , vol. 03, no. 12, pp. 1141–1147, 2010.
9. A. M. Kane, "On the Use of Continued Fractions for Mutual Authentication," Int. J. Inf. Secur. Sci. , vol. 1, no. 3, 1995.
10. A. M. Kane, "On the use of continued fractions for electronic cash," Int. J. Comput. Sci. Secur. , no. 4, pp. 136–148, 2013
11. Lin and S. Chang, "Generating Robust Digital Signature for Image / Video Authentication," Multimedia and Security Workshop at ACM Multimedia '98, Bristol, U. K. , September, 1998.
12. M. F. M. Mursi, G. M. R. Assassa, H. A. Aboalsamh, and K. Alghathbar, "A DCT-Based Secure JPEG Image Authentication Scheme,", World Academy of Science, Engineering and Technology, vol 3, pp. 611–616, 2009.
13. C. Chang, J. Chuang, and T. Chen, "Recognition of Image Authenticity Using Significant DCT Coefficients Quantization," Informatica, vol. 26, pp. 359–366, 2002.
14. Van Schyndel, R. G. , Tirkel, A. Z. and Osborne, C. F. , 1994. "A digital watermark", Proceedings of IEEE International Conference on Image Processing, Vol. 2, pp. 86-90.
15. Mitr, A. , "On Pseudo-Random and Orthogonal Binary Spreading Sequences", International Journal of Information and Communication Engineering. 2008.
16. H. Niederreiter, Sequences with almost perfect linear complexity profile, Advances in Cryptology - EUROCRYPT' 87: Workshop on the Theory and Application of Cryptographic Techniques, Amsterdam, The Netherlands, vol. 304, 37-51, 198
17. C. D. Olds, "Continued Fractions", Random House, 1963.
18. O. Perron, "Die Lehre Von Den Kettenbrüchen", 3rd ed. (1954)
19. A. M. Kane, "On the use of Continued Fractions for Stream Ciphers" In Proceedings of Security and Management 2009, Las Vegas, USA.
20. A. G. B. Lauder, Continued fractions and sequences, Ph. D. thesis, University of London, 1999.
21. J. Pieprzyk, H. Ghodosi, C. Charnes, R. Safavi-Naini Cryptography based on transcendental numbers, Information Security and Privacy, Lecture Notes in Computer Science, Vol. 1172, Proceedings, First Australasian Conference on Information Security and Privacy, ACISP'96,Wollongong, Australia, 1996.
22. C. Shine, Method and apparatus of using irrational numbers in random number generators for cryptography United States Patent, Application No. 10/190455, Application Date: Jul 3 2002.
23. P. Jayashree, T. Padma, "Image Watermarking using PQ sequences", Proceedings of the International Conference on Emerging Research in Computing, Information, Communication and Applications (Vol 3) Elsevier Publications 2014, ISBN 9789351072638
24. Parthasarathy, Arvind Kumar, Kak, Subhash, "An Improved Method of Content Based Image Watermarking," , IEEE Transactions on Broadcasting, vol. 53, no. 2, pp. 468–479, 2007.
25. S. Garg, "An Efficient Method for Digital Image Watermarking Based on PN Sequences," Int. J. Comput. Sci. Eng. , vol. 4, no. 09, pp. 1550–1561, 2012
26. Jayashree S. Pillai, T. Padma, The analysis of PQ sequences generated from continued fraction for use as pseudorandom sequences in Cryptographic Applications, Springer AISC Series, 2015.

Authentication Pq Sequences Feature Vector Key Vector Textured Regions Content Based Watermark.