Robust and Secure Data Hiding for PDF Text Document


IEICE TRANSACTIONS on Information and Systems   Vol.E102-D   No.1   pp.41-47
Publication Date: 2019/01/01
Publicized: 2018/10/19
Online ISSN: 1745-1361
DOI: 10.1587/transinf.2018MUP0003
Type of Manuscript: Special Section PAPER (Special Section on Enriched Multimedia — Making Multimedia More Convenient and Safer —)
portable document format,  quantization index modulation,  dither modulation,  permutation,  

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The spaces between words and paragraphs are popular places for embedding data in data hiding techniques for text documents. Due to the low redundancy in text documents, the payload is limited to be small. As each bit of data is independently inserted into specific spaces in conventional methods, a malicious party may be able to modify the data without causing serious visible distortions. In this paper, we regard a collection of space lengths as a one-dimensional feature vector and embed watermark into its frequency components. To keep the secrecy of the embedded information, a random permutation and dither modulation are introduced in the operation. Furthermore, robustness against additive noise is enhanced by controlling the payload. In the proposed method, through experiments, we evaluated the trade-off among payload, distortion, and robustness.