A Review of Text Watermarking: Theory, Methods, and Applications <s> 9) MENG et al. (2011) <s> In the study of copyright protection of digital text, a Chinese text Zero-Watermark scenario based on space model was proposed. The construction and detection model of the watermark was presented, and the core algorithm of the watermark was designed in this paper. In the scenario, the three-dimensional model was constructed by using the two-dimensional coordinate of word-level and the sentence weights of sentence-level. By mapping all sentences to the three-dimensional model, the three-dimensional space modal of whole text was produced, which was the eigenvector of this paper. Therefore, the Chinese text zero-watermark was constructed. Furthermore, the effectiveness and feasibility of the algorithm was proved with algorithm simulation. The simulation results also showed that the algorithm had good robustness, especially for syntactic transfer?Csynonyms replacement and shear attack. <s> BIB001 </s> A Review of Text Watermarking: Theory, Methods, and Applications <s> 9) MENG et al. (2011) <s> study of content authentication and tamper detection of digital text documents, a novel English text zero- watermarking approach based on probabilistic patterns proposed in this paper. Hidden Markov model was presented, and the core algorithm of the watermark generation and detection was designed in this paper. In the proposed approach, Hidden Markov model letter-level based of order one was constructed for text analysis and watermark generation based on interrelationship between contents of host text document by using the two-dimensional matrix coordinate of probabilistic weights of states and transitions. However, we can extracted this watermark later using extraction and detection algorithm to identify the status of text document such as authentic, tampered, etc. Furthermore, the effectiveness and feasibility of our proposed algorithm was proved with algorithm experiments and comparative with other recently approach under random insertion and deletion attacks in localized and dispersed form on 6 text datasets of varying length. Results showed that our proposed algorithm is more secure, had better robustness, and always detects tampering attacks occurred randomly on text even when the tampering volume is low or high. <s> BIB002
Zero watermarking based on space models was also proposed by Meng et al. whereby the zero watermark was constructed from a 3-D model using the 2-D coordinates of word level and the sentence weights of the sentence-level. The 2-D word space structure consists of the length and frequency of the words and is extended into a 3-D model. The text watermark was constructed by mapping the sentence to the 3-D model. This algorithm is tested with three most common attacks; syntactic transformation attack, synonym replacement attack, and deleting attack, in order to test its performance. In the syntactic transformation attack, the higher percentage of transformation yields a lower watermark detection rate. The same is the case with the synonym replacement attack and the deletion attack. This method improves robustness and provide good imperceptibility and security BIB001 . The research team proposed a watermarking approach based on Markov's model where the probabilistic features of the cover file are used to generate the watermark key. The watermark information of the text is analysed using the hidden Markov model where it is stored for authentication of the document. It offers protection against attacks with a watermark distortion percentage rate of greater than one for all insertion and deletion attacks BIB002 .