Robust Digital Image Watermarking against Cropping and Salt & Pepper Noise using two-step Sudoku

Several methods are exploited to watermark digital images as a safety measure for storing information, but an attacker can destroy the information by cropping a segment of the watermarked image or doing salt and pepper noise. In recent years, numerous schemes were proposed that reduce the impact of such attacks. A new method has been proposed to confront cropping attack and salt and pepper noise that is carried out using two Sudoku tables. In this method, the watermark image is scattered in two Sudoku table layouts with different solutions and is watermarked in the host image with Least Significant Bit(LSB). Using this method, the watermark image is repeated 81 times in the host image, and to this effect the watermark image can be reconstructed using other segments when cropped or salt and pepper noise by the attacker. Both Sudokus used in this paper are in the classic 9x9 form and using this method, resistance to cropping attacks increases up to 98.8% and resistance to salt and pepper noise increase up to 80%