Method for adding dynamic watermark in OFD document

Abstract

The invention discloses a method for adding a dynamic watermark in an OFD document, and the method comprises the steps: carrying out the vectorization processing of the watermark content, and obtaining the vectorization data of an original watermark; calculating the watermark vector data by randomly adopting a digest algorithm through a random factor to obtain a digest value of the watermark vector data; embedding the digest value into the vectorized data to obtain unique watermark data on the target insertion page; and a plurality of calculation factors are introduced, and the watermark position on the target insertion page is dynamically calculated. According to the method for adding the dynamic watermark in the OFD document, vectorization of the watermark data is achieved, the watermark data added to each page in the document are different by introducing multiple calculation factors and intelligent algorithms and establishing the dynamic watermark model, the concealment of the watermark data is greatly improved, and the watermarking efficiency is improved. The recognition complexity of watermark data is high, the regularity of the watermark data is very difficult to find, and the watermark data is difficult to remove.

Description

technical field [0001] The invention relates to the technical field of electronic document processing, in particular to a method for adding a dynamic watermark to an OFD document. Background technique [0002] In the process of application and circulation of OFD documents, while reading OFD documents, there is often a need to add watermarks to OFD documents. For the purpose of multiplexing, a watermark will be added to the e-book in the OFD format, and there are many such application scenarios. [0003] The traditional method is to add the same watermark at a fixed position on the pages within a certain page range of the OFD document. The basic process includes: establishing a watermark data model, defining the content, location and page application scope of the watermark; writing the watermark data in the OFD document according to the OFD standard; saving the OFD document. In the prior art, the watermark added in the OFD document has a fixed page application range, a fixe...

AI Technical Summary

Problems solved by technology

In the existing technology, the page application range of the watermark added in the OFD document is fixed, the position where it appears on the page is fixed, the content of the watermark is fixed, and its content is relatively easy to identify, so this On the whole, the watermark has a strong regularity and is not concealed. People who have a certain understanding of the OFD format can easily find the law, and can remove the watermark data through manual or technical means, and at the same time do not damage the original document content of the OFD document. In this case, it loses the significance of protecting documents through watermarks, restricting malicious transmission and reusing documents

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