IronPDF vs Docusign - PDFにデジタル署名を追加する方法

using IronPdf;
using IronPdf.Signing;
using System.Security.Cryptography.X509Certificates;

public class Program
{
    static void Main(string[] args)
    {
        // Load an existing PDF document
        PdfDocument pdf = PdfDocument.FromFile("invoice.pdf");

        // Load a certificate from a .pfx file
        X509Certificate2 cert = new X509Certificate2("IronSoftware.pfx", "your-password", X509KeyStorageFlags.Exportable);

        // Create a PDF signature using the certificate
        var sig = new PdfSignature(cert);

        // Sign the PDF document
        pdf.Sign(sig);

        // Save the signed PDF document
        pdf.SaveAs("signed.pdf");
    }
}

Imports IronPdf
Imports IronPdf.Signing
Imports System.Security.Cryptography.X509Certificates

Public Class Program
	Shared Sub Main(ByVal args() As String)
		' Load an existing PDF document
		Dim pdf As PdfDocument = PdfDocument.FromFile("invoice.pdf")

		' Load a certificate from a .pfx file
		Dim cert As New X509Certificate2("IronSoftware.pfx", "your-password", X509KeyStorageFlags.Exportable)

		' Create a PDF signature using the certificate
		Dim sig = New PdfSignature(cert)

		' Sign the PDF document
		pdf.Sign(sig)

		' Save the signed PDF document
		pdf.SaveAs("signed.pdf")
	End Sub
End Class

using IronPdf;

PdfDocument pdf = PdfDocument.FromFile("signed_test_document.pdf");

// Verify the digital signatures in the PDF document
bool isValid = pdf.VerifyPdfSignatures();
if (isValid)
{
    Console.WriteLine("The digital signature is valid.");
}
else
{
    Console.WriteLine("The digital signature is invalid or missing.");
}

Imports IronPdf

Private pdf As PdfDocument = PdfDocument.FromFile("signed_test_document.pdf")

' Verify the digital signatures in the PDF document
Private isValid As Boolean = pdf.VerifyPdfSignatures()
If isValid Then
	Console.WriteLine("The digital signature is valid.")
Else
	Console.WriteLine("The digital signature is invalid or missing.")
End If