Method for Protection of PDF Documents against Counterfeiting using Semi-Fragile Watermarking
Pavel Dikanev, Yuliya Vybornova · 2021 International Conference on Information Technology and Nanotechnology (ITNT) · 2021
This paper proposes a new method for protection of PDF documents from counterfeiting, which also provides the ability to localize forged fragments. The method is based on embedding of digital watermark represented as QR code, which encodes a binary string, comprising a secret key and a page number. A unique binary digital image (QR code) is introduced into the least significant bits of the discrete wavelet transform coefficients of each document page. The analysis of the extracted binary string allows to detect and localize such attacks as page addition, deletion, and reordering, while the analysis of the QR code image reveals a fake fragment on a particular page. An experimental study of the method efficiency is performed. According to the experimental results, the method is suitable for PDF document authentication, as well as for steganographic transmission of a secret message.