IMPLEMENTASI ASYMMETRIC-WATERMARKING BERBASIS PERMUTASI RC-4 PADA KOEFISIEN DWT CITRA DIGITAL

• Main Authors: , Mina Naidah Gani, , Dr. Eng. Ir. Risanuri Hidayat, M.Sc.
• Format: Theses and Dissertations NonPeerReviewed
• Published: [Yogyakarta] : Universitas Gadjah Mada 2011
• Subjects: ETD
• Online Access: https://repository.ugm.ac.id/90860/; http://etd.ugm.ac.id/index.php?mod=penelitian_detail&sub=PenelitianDetail&act=view&typ=html&buku_id=53157
• Institution: Universitas Gadjah Mada

Accessing the digital image data is increasingly easy and widespread, causing the need for a security system that protects information from those who are not responsible. One method of protection for digital image data is the Digital Image Watermarking. Discrete Wavelet Transform (DWT) is widely used in the domain of watermarking techniques. By always assume that the algorithm can be owned by anyone, asymmetric watermarking method can bridge the digital image so that watermark contained in the host remains safe. Permutations which are difficult to trace is one of solving this problem. RC-4 permutation method based on logistic map, with the concept of embedding a digital image of the dwt coefficients proposed by several researchers. Test results show that the DWT domain is more robust against geometric attacks rotation and resizing images than in DCT domain. Watermark detection, performed by applying the correlation test, obtained is always positive on all nonmalicious attacks (cropping, compression, noise, sharpening resizing, and rotation), except in size reduction watermarked images smaller than 22% also noise and salt & peppers on a coefficient greater than 0.1%. While on extraction, throughout the testing without an attack or with non-malicious attacks, the watermark extracted, except for cutting images to watermark permuted, reduction and JPEG compression with quality less than 100%. Setting some coefficients such as the coefficient of the insertion threshold, the watermark strength, and coefficient of the watermark itself, can produce a reliable copyright on a host.