如何移除PDF文件上的密碼

// Import necessary namespaces
using IronPdf;
using System.Collections.Generic;
using System.Drawing;

public class PDFExtractor
{
    public void ExtractDataFromPDF()
    {
        // Open a 128-bit encrypted PDF file by providing the filename and password
        using PdfDocument pdf = PdfDocument.FromFile("encrypted.pdf", "password");

        // Extract all text from the PDF document
        string allText = pdf.ExtractAllText();

        // Extract all images from the PDF document
        IEnumerable<Image> allImages = pdf.ExtractAllImages();

        // Iterate over each page in the PDF document
        for (var index = 0; index < pdf.PageCount; index++)
        {
            int pageNumber = index + 1;

            // Extract text from the specific page
            string text = pdf.ExtractTextFromPage(index);

            // Extract images from the specific page
            IEnumerable<Image> images = pdf.ExtractImagesFromPage(index);

            // Code to process the extracted text and images
            //...
        }
    }
}

' Import necessary namespaces
Imports IronPdf
Imports System.Collections.Generic
Imports System.Drawing

Public Class PDFExtractor
	Public Sub ExtractDataFromPDF()
		' Open a 128-bit encrypted PDF file by providing the filename and password
		Using pdf As PdfDocument = PdfDocument.FromFile("encrypted.pdf", "password")
	
			' Extract all text from the PDF document
			Dim allText As String = pdf.ExtractAllText()
	
			' Extract all images from the PDF document
			Dim allImages As IEnumerable(Of Image) = pdf.ExtractAllImages()
	
			' Iterate over each page in the PDF document
			For index = 0 To pdf.PageCount - 1
				Dim pageNumber As Integer = index + 1
	
				' Extract text from the specific page
				Dim text As String = pdf.ExtractTextFromPage(index)
	
				' Extract images from the specific page
				Dim images As IEnumerable(Of Image) = pdf.ExtractImagesFromPage(index)
	
				' Code to process the extracted text and images
				'...
			Next index
		End Using
	End Sub
End Class