PDF digital signature method and system and PDF digital signature verification method and system

Abstract

The invention provides a PDF digital signature method. The PDF digital signature method includes the steps that byte range data corresponding to a digital signature are calculated according to a PDF file to be signed and attribute information of the digital signature; an abstract value is calculated according to the byte range data, and a countersignature digital signature result is calculated according to the abstract value; a main digital signature result is calculated according to the abstract value; the countersignature digital signature result is packaged in the main digital signature result, and the digital signature result obtained after packaging is stored in a PDF file digital signature dictionary. Correspondingly, the invention further provides a PDF digital signature system and a PDF digital signature verification method and system. By means of the PDF digital signature method and system and the PDF digital signature verification method and system in the technical scheme, the same version of the PDF file can be subjected to digital signing for multiple times, and the shared signature of the content of the same file is achieved; as the countersignature signature result of a user-defined algorithm is packaged into the main signature result of a standard algorithm, the compatibility between the PDF file signed with the user-defined algorithm and a universal PDF reader is achieved.

Description

technical field [0001] The invention relates to the technical field of data signatures, in particular to a PDF digital signature method, a PDF digital signature verification method, a PDF digital signature system and a PDF digital signature verification system. Background technique [0002] As PDF has become one of the mainstream file exchange formats, the digital signature of PDF files has become an important technical means to ensure the authenticity and integrity of files. According to the "ISO32000:1-2008 Document Management--Portable Document Format--Part 1: PDF1.7" specification, the signature range of PDF files is specified by the byte range (ByteRange) in the PDF signature dictionary, and the general value is Remove other contents of the document other than the signature result (Contents) in the signature dictionary. The process of PDF signature is as follows figure 1 As shown, the specific description is as follows: [0003] 1. Calculate the byte range data corres...

AI Technical Summary

Problems solved by technology

[0009] 1. It does not meet the business requirements of joint signing of the same content. Since the byte range covered by each signature is different, the content of the document protected by each digital signature is different.

[0010] 2. The performance of signature verification is relatively low, and the reader needs to extract the data of each signature for verification;

[0015] 1. Poor user experience: Using the existing technology, signature verification depends on a dedicated plug-in. For a conventional client without a plug-in installed, a document signed with a custom algorithm will display that the signature cannot be verified or the verification fails. completely unconfirmed

[0016] 2. Difficulty in distribution and maintenance: the reader plug-in needs to be installed in a specific subdirectory under the installation directory of the client reader. The subdirectory is also different for different versions of the reader. For example, the plug-in subdirectory of Acrobat is \Acrobat\plug_ins, while The plug-in subdirectory of Adobe Reader is Reader\plug_ins

Due to the complexity of the client environment, the distribution and maintenance of custom signature algorithm verification plugins are very difficult

[0017] 3. The cost is high: the use of the plug-in interface of the universal reader requires the development license of the source manufacturer, which increases the development cost

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