Enhancing data leakage tracing: a novel digital watermarking method for document files
Tong Kong, Hao Zhou, Haikuo Qu, Jie Chen, Chonghua Wang, Jun Li · 2024
With the development of informatization, the value of data is rapidly escalating. The security and controllability of data have become increasingly important. Digital watermarking is an effective method for data tracing and copyright protection. However, most digital watermarking methods focus on images, audio, and video files, with few applications dedicated to document file protection. Therefore, we present an imperceptible and cryptographic digital watermarking method for document files, inspired by the image digital watermarking based on the Least Significant Bit (LSB). Firstly, the watermark information is divided into segments which will be encrypted into ciphertexts separately. Then, these ciphertexts are converted into a binary byte stream and embedded into the LSB of the characters’ color information in document files. Finally, we design an algorithm combined with the chaos theory to execute the embedding process, ensuring its controllability and randomness. Meanwhile, we design a watermark extraction method with a voting mechanism to restore and verify the watermark information. This method can resist the destruction of document files (such as adding, deleting, or modifying some characters) and enhance the stability and traceability of watermark information. The results demonstrate that the accuracy of information extraction is still nearly 80%, even when up to 40% of the document's characters are deleted, enabling quick verification of document copyrights and rapid tracing of the data source.