Because there are different modification types of deleting characters and inserting characters in text documents, the algorithms for image authentication can not be used for text documents authentication directly. A t...Because there are different modification types of deleting characters and inserting characters in text documents, the algorithms for image authentication can not be used for text documents authentication directly. A text watermarking scheme for text document authentication is proposed in this paper. By extracting the features of character cascade together with the user secret key, the scheme combines the features of the text with the user information as a watermark which is embedded into the transformed text itself. The receivers can verify the integrity and the authentication of the text through the blind detection technique. A further research demonstrates that it can also localize the tamper, classify the type of modification, and recover part of modified text documents. The aforementioned conclusion has been proved by both our experiment results and analysis.展开更多
To detect and recover random tampering areas,a combined-decision-based self-embedding watermarking scheme is proposed herein.In this scheme,the image is first partitioned into 2×2 size blocks.Next,the high 5 bits...To detect and recover random tampering areas,a combined-decision-based self-embedding watermarking scheme is proposed herein.In this scheme,the image is first partitioned into 2×2 size blocks.Next,the high 5 bits of a block’s average value is embedded into its offset block.The tampering type of block is detected by comparing the watermarks of its pre-offset and post-offset blocks.The theoretical analysis and experiments demonstrate that the proposed scheme not only has a lower ratio of false detection but also better performance with regard to avoiding random tampering.展开更多
To address the problems of the inferior localization and high probability of false rejection in existing self-recovery fragile watermarking algorithms, this paper proposes a new self-recovery fragile watermarking sche...To address the problems of the inferior localization and high probability of false rejection in existing self-recovery fragile watermarking algorithms, this paper proposes a new self-recovery fragile watermarking scheme with superior localization, and further discusses the probability of false rejection （PFR） and the probability of false acceptance （PFA） of the proposed scheme. Moreover, four measurements are defined to evaluate the quality of a recovered image. In the proposed algorithm, the original image is divided into 2×2 blocks to improve localization precision and decrease PFR under occurrence of random tampering. The PFR under occurrence of region tampering can be effectively decreased by randomly embedding the watermark of each block in conjunction with a novel method of tamper detection. Compared with the current self-recovery fragile watermarking algorithms, the proposed scheme not only resolves the tamper detection problem of self-embedding watermarking, but also improves the robustness against the random tampering of self-embedding watermarking. In addition, the subjective measurements are provided to evaluate the performance of the self-recovery watermarking schemes for image authentication.展开更多
基金Supported by the National Natural Science Foun-dation of China (60373062 60573045)
文摘Because there are different modification types of deleting characters and inserting characters in text documents, the algorithms for image authentication can not be used for text documents authentication directly. A text watermarking scheme for text document authentication is proposed in this paper. By extracting the features of character cascade together with the user secret key, the scheme combines the features of the text with the user information as a watermark which is embedded into the transformed text itself. The receivers can verify the integrity and the authentication of the text through the blind detection technique. A further research demonstrates that it can also localize the tamper, classify the type of modification, and recover part of modified text documents. The aforementioned conclusion has been proved by both our experiment results and analysis.
基金This work was supported in part by the National Natural Science Foundation of China(No.61401512,61602508,61772549,6141512 and U1636219)the National Key R&D Program of China(No.2016YFB0801303 and 2016QY01W0105)+1 种基金the Key Technologies R&D Program of Henan Province(No.162102210032)the Key Science and Technology Research Project of Henan Province(No.152102210005).
文摘To detect and recover random tampering areas,a combined-decision-based self-embedding watermarking scheme is proposed herein.In this scheme,the image is first partitioned into 2×2 size blocks.Next,the high 5 bits of a block’s average value is embedded into its offset block.The tampering type of block is detected by comparing the watermarks of its pre-offset and post-offset blocks.The theoretical analysis and experiments demonstrate that the proposed scheme not only has a lower ratio of false detection but also better performance with regard to avoiding random tampering.
基金the Program for New Century Excellent Talents in University of China (Grant No.NCET-05-0794)Southwest Jiaotong University Doctors Innovation Funds (2007)Application Basic Foundation of Sichuan Province, China (Grant No.2006 J13-10-5)
文摘To address the problems of the inferior localization and high probability of false rejection in existing self-recovery fragile watermarking algorithms, this paper proposes a new self-recovery fragile watermarking scheme with superior localization, and further discusses the probability of false rejection （PFR） and the probability of false acceptance （PFA） of the proposed scheme. Moreover, four measurements are defined to evaluate the quality of a recovered image. In the proposed algorithm, the original image is divided into 2×2 blocks to improve localization precision and decrease PFR under occurrence of random tampering. The PFR under occurrence of region tampering can be effectively decreased by randomly embedding the watermark of each block in conjunction with a novel method of tamper detection. Compared with the current self-recovery fragile watermarking algorithms, the proposed scheme not only resolves the tamper detection problem of self-embedding watermarking, but also improves the robustness against the random tampering of self-embedding watermarking. In addition, the subjective measurements are provided to evaluate the performance of the self-recovery watermarking schemes for image authentication.
