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PDF file digital signature and verification method and system

A digital signature and file technology, applied in digital transmission systems, transmission systems, digital data protection, etc., can solve problems such as hidden signature invalidation, and achieve the effect of security guarantee

Active Publication Date: 2014-03-05
GUANGDONG CERTIFICATE AUTHORITY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Aiming at the problem that the traditional digital signature method is used to add hidden signatures, the present invention provides a PDF file digital signature and its verification method and system

Method used

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  • PDF file digital signature and verification method and system
  • PDF file digital signature and verification method and system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0044] see Figure 4 Shown, a kind of PDF file digital signature method comprises the following steps:

[0045] Step S101 , acquiring the data to be authenticated (Array) of the PDF file to be signed and the data length (Length) of the data to be authenticated.

[0046] As a preferred embodiment, the data to be authenticated obtained in the present invention can be the entire content of the PDF file to be signed; the data length of the obtained data to be authenticated can be the length of the PDF file to be signed .

[0047] Step S102, constructing the original text (Text) of the digital signature according to the data to be authenticated Array and the data length Length; the details can be as follows: Text=Length||Array; where the || symbol represents a concatenation operation; Length is a 32-bit integer value .

[0048] Step S103, calculating a digital signature value according to the original text of the digital signature, the user's public key certificate and the user'...

Embodiment 2

[0058] By adding a hidden signature to the PDF file in the first embodiment above, any original PDF text can be authenticated. This embodiment provides a method in which the added hidden signature only authenticates the data bound by UR3. see Figure 5 Shown, a kind of PDF file digital signature method comprises the following steps:

[0059] Step S201, obtain the UR3 dictionary of the PDF file to be signed, and read the byte range (ByteRange) in the UR3 dictionary, and then go to step S202.

[0060] Step S202, calculate the data length of the PDF file according to the byte range ByteRange, and obtain the data to be authenticated of the PDF file according to the data length. Specifically, since the ByteRange format of UR3 is {Offset1, Length1, Offset2, Length2}, the data length Length=Offset2+Length2 can be calculated accordingly; and starting from offset address 0, read the data Array of Length bytes ( That is, data to be authenticated), these data are form data with UR3 si...

Embodiment 3

[0067] Corresponding to Embodiment 1 and Embodiment 2 above, the present invention also provides a PDF file digital signature system, such as Image 6 shown, including:

[0068] Data obtaining module 101, for obtaining the data to be authenticated and the data length of the PDF file to be signed;

[0069] Original text construction module 102, for constructing the original text of digital signature according to described data to be authenticated and data length;

[0070] The digital signature value calculation module 103 is used to calculate the digital signature value according to the original text of the digital signature, the user public key certificate and the user private key;

[0071] A digital signature adding module 104, configured to write the digital signature value into the PDF file.

[0072] As a preferred embodiment, the digital signature adding module 104 may include:

[0073] The digital signature dictionary adding module is used to add a digital signature di...

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Abstract

The invention provides a PDF file digital signature and verification method and system. The PDF file digital signature method includes the following steps of obtaining data, to be verified, of a PDF file to be signed and the data length of the data to be verified; creating the text of a digital signature according to the data to be verified and the data length; calculating a digital signature value according to the text of the digital signature, a user public key certificate and a user private secret key; writing the digital signature value into the PDF file. According to the PDF file digital signature and verification method and system, an invisible signature which can not be recognized by a client is created, data of the invisible signature can be reedited by the user, and effectiveness of the invisible signature can not be destroyed.

Description

technical field [0001] The present invention relates to the technical field of digital signatures and authentication services, in particular to a PDF file digital signature method, a PDF file digital signature system, a PDF file digital signature verification method, and a PDF file digital signature verification system . Background technique [0002] PDF is the English abbreviation of Portable Document Format, which is a unique cross-platform file format developed by Adobe. This file format has nothing to do with the operating system platform, which means that PDF files can be used regardless of whether they are Windows, Unix or Mac OS operating systems. This feature makes it an ideal document format for electronic document distribution and digital information dissemination on the Internet. PDF format files have become an industrial standard adopted in the process of informatization in various industries. [0003] In addition, digital signature has become the most widely ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F21/64H04L9/32
CPCG06F21/64H04L9/3247H04L9/3263
Inventor 张永强
Owner GUANGDONG CERTIFICATE AUTHORITY
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