How to Decrypt PDF and Extract Image from It – C#/VB.NET
Last time, I had introduced methods about PDF security, including how to encrypt PDF and add digital certificate. In this post, I want to show another method about how to decrypt PDF document with C#/VB.NET.
In my example, I have an encrypted PDF document, which saves an image about employee information. What I will do is to decrypt this document with password and extract image from it.
Also, I use s component Spire.PDF in my method. Therefore, I add its dll file as reference when starting with the following steps.
Steps:
- Declare a string encryptedPdf and assign its value as the document which has been encrypted. Then, create a new PDF document. There are two parameters passed to PdfDocument method, string encryptedPdf and password, which is used to open the encrypted document. It means that the new PDF document we create is original document which has been decrypted.
- Extract Image. Suppose that there are many pages in document. We need to extract images from each page.
- Save and launch image file.
Original Document
Main Coding:
C#
using System;
using System.Drawing;
using Spire.Pdf;
namespace PDFDecrypt
{
class Decrypt
{
static void Main(string[] args)
{
//Create Document
String encryptedPdf = @"D:\work\My Documents\Encryption.pdf";
PdfDocument doc = new PdfDocument(encryptedPdf, "123456");
//Extract Image
Image image = doc.Pages[0].ImagesInfo[0].Image;
doc.Close();
//Save
image.Save("EmployeeInfo.png", System.Drawing.Imaging.ImageFormat.Png);
//Launch
System.Diagnostics.Process.Start("EmployeeInfo.png");
}
}
}
VB.NET
Imports System.Drawing
Imports Spire.Pdf
Module Decrypt
Sub Main()
'Create Document
Dim encryptedPdf As String = "D:\work\My Documents\Encryption.pdf"
Dim doc As New PdfDocument(encryptedPdf, "123456")
'Extract Image
Dim image As Image = doc.Pages(0).ImagesInfo(0).Image
doc.Close()
'Save
image.Save("EmployeeInfo.png", System.Drawing.Imaging.ImageFormat.Png)
'Launch
System.Diagnostics.Process.Start("EmployeeInfo.png")
End Sub
End Module
Result Shown by Following:
______________________________________________________________________________________________
Click Here to Learn more about Spire.PDF
Click Here to Download Spire.PDF
Related Posts:
Create PDF Digital Certificate
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