Three layer authentications with a spiral block mapping to prove authenticity in medical images

Digital medical image has a potential to be manipulated by unauthorized persons due to advanced communication technology. Verifying integrity and authenticity have become important issues on the medical image. This paper proposed a self-embedding watermark using a spiral block mapping for tamper detection and restoration. The block-based coding with the size of 3x3 was applied to perform selfembedding watermark with two authentication bits and seven recovery bits. The authentication bits are obtained from a set of condition between sub-block and block image, and the parity bits of each sub-block. The authentication bits and the recovery bits are embedded in the least significant bits using the proposed spiral block mapping. The recovery bits are embedded into different sub-blocks based on a spiral block mapping. The watermarked images were tested under various tampered images such as blurred image, unsharp-masking, copy-move, mosaic, noise, removal, and sharpening. The experimental results show that the scheme achieved a PSNR value of about 51.29 dB and a SSIM value of about 0.994 on the watermarked image. The scheme showed tamper localization with accuracy of 93.8%. In addition, the proposed scheme does not require external information to perform recovery bits. The proposed scheme was able to recover the tampered image with a PSNR value of 40.45 dB and a SSIM value of 0.994

Enhancing fragility of zero-based text watermarking utilizing effective characters list

Text is an important medium used for sharing information worldwide. For a text document, digital watermarking is an efficient way for copyright protection, authentication, tamper proofing, to name but a few. In this paper, a zero-based watermarking approach is proposed for document authentication and tamper detection. To enhance the fragility of watermark, the proposed text watermarking approach can be comfortably utilized – based on the Effective Characters List (ECL) for watermark generation. The ECL method is generated for English text zero-watermarking by maintaining the contents of the original document and constructing the watermark by formulating the smooth transition between the selected characters in the documents. The evaluation of the proposed watermarking approach is based on three famous watermarking attacks including deletion, insertion, and reordering with an accuracy of 80.76%, 80.36%, and 88.1%, respectively. For a fair evaluation, a comparison is put forth with a recent zero-based watermarking method - clearly showing that the proposed method outperforms existing with greater accuracy. © 2019, Springer Science+Business Media, LLC, part of Springer Nature

AuSR1 : Authentication and self-recovery using a new image inpainting technique with LSB shifting in fragile image watermarking

With the rapid development of multimedia technology, editing and manipulating digital images have become more accessible than ever. This paper proposed color image authentication based on blind fragile image watermarking for tamper detection and self-recovery named AuSR1. The AuSR1 divides each channel of the cover image into non-overlapping blocks with the size of 2 × 2 pixels. The authentication data is embedded into the original block location, while the recovery data is embedded into the distant location from the original location based on the block mapping algorithm. The watermark data is then embedded into the 2 LSB to achieve high quality of the recovered image under tampering attacks. In addition, the permutation algorithm is applied to ensure the security of the watermark data. The AuSR1 utilizes a three-layer authentication algorithm to achieve a high detection rate. The experimental results show that the scheme produced a PSNR value of 45.57 dB and an SSIM value of 0.9972 of the watermarked images. Furthermore, the AuSR1 detected the tampered area of the images with a high precision value of 0.9943. In addition, the recovered image achieved a PSNR value of 27.64 dB and an SSIM value of 0.9339 on a 50% tampering rate

Optimisation of Tamper Localisation and Recovery Watermarking Techniques

Digital watermarking has found many applications in many fields, such as: copyright tracking, media authentication, tamper localisation and recovery, hardware control, and data hiding. The idea of digital watermarking is to embed arbitrary data inside a multimedia cover without affecting the perceptibility of the multimedia cover itself. The main advantage of using digital watermarking over other techniques, such as signature based techniques, is that the watermark is embedded into the multimedia cover itself and will not be removed even with the format change. Image watermarking techniques are categorised according to their robustness against modification into: fragile, semi-fragile, and robust watermarking. In fragile watermarking any change to the image will affect the watermark, this makes fragile watermarking very useful in image authentication applications, as in medical and forensic fields, where any tampering of the image is: detected, localised, and possibly recovered. Fragile watermarking techniques are also characterised by a higher capacity when compared to semi-fragile and robust watermarking. Semifragile watermarking techniques resist some modifications, such as lossy compression and low pass filtering. Semi-fragile watermarking can be used in authentication and copyright validation applications whenever the amount of embedded information is small and the expected modifications are not severe. Robust watermarking techniques are supposed to withstand more severe modifications, such as rotation and geometrical bending. Robust watermarking is used in copyright validation applications, where copyright information in the image must remains accessible even after severe modification. This research focuses on the application of image watermarking in tamper localisation and recovery and it aims to provide optimisation for some of its aspects. The optimisation aims to produce watermarking techniques that enhance one or more of the following aspects: consuming less payload, having better recovery quality, recovering larger tampered area, requiring less calculations, and being robust against the different counterfeiting attacks. Through the survey of the main existing techniques, it was found that most of them are using two separate sets of data for the localisation and the recovery of the tampered area, which is considered as a redundancy. The main focus in this research is to investigate employing image filtering techniques in order to use only one set of data for both purposes, leading to a reduced redundancy in the watermark embedding and enhanced capacity. Four tamper localisation and recovery techniques were proposed, three of them use one set of data for localisation and recovery while the fourth one is designed to be optimised and gives a better performance even though it uses separate sets of data for localisation and recovery. The four techniques were analysed and compared to two recent techniques in the literature. The performance of the proposed techniques vary from one technique to another. The fourth technique shows the best results regarding recovery quality and Probability of False Acceptance (PFA) when compared to the other proposed techniques and the two techniques in the literature, also, all proposed techniques show better recovery quality when compared to the two techniques in the literature