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I tried verifying digitally signed aadhar copy with code snippet provided by syncfusion but it is throwing an exception. Below is the code I tried with. Please help me if I am doing anything wrong.

using System;

using System.IO;

using System.Security.Cryptography.X509Certificates;

using Syncfusion.Pdf.Parsing;

using Syncfusion.Pdf.Security;

namespace VerifyAadhar


    class Program


        static void Main(string[] args)


            //System.IO.Stream f =

            //Load an existing PDF document.

            PdfLoadedDocument document = new PdfLoadedDocument(File.ReadAllBytes("../../../aadhar.pdf"));

            //Load PDF form.

            PdfLoadedForm form = document.Form;

            X509Store store = new X509Store("MY", StoreLocation.CurrentUser);

            store.Open(OpenFlags.ReadOnly | OpenFlags.OpenExistingOnly);

            X509Certificate2Collection collection = (X509Certificate2Collection)store.Certificates;

            if (form != null)


                foreach (PdfLoadedField field in form.Fields)


                    if (field is PdfLoadedSignatureField)


                        PdfLoadedSignatureField signatureField = field as PdfLoadedSignatureField;

                        //Check whether the signature is signed.

                        if (signatureField.IsSigned)


                            PdfSignatureValidationResult result = signatureField.ValidateSignature(collection); //certificates

                            if (result.IsSignatureValid)

                                Console.WriteLine("Signature is valid");


                                Console.WriteLine("Signature is invalid");

                            //Retrieve the signature information.


                            Console.WriteLine("Digitally Signed by: " + signatureField.Signature.Certificate.IssuerName);

                            Console.WriteLine("Valid From: " + signatureField.Signature.Certificate.ValidFrom);

                            Console.WriteLine("Valid To: " + signatureField.Signature.Certificate.ValidTo);

                            Console.WriteLine("Signature Algorithm : " + result.SignatureAlgorithm);

                            Console.WriteLine("Hash Algorithm : " + result.DigestAlgorithm);

                            Console.WriteLine("Cryptographics Standard : " + result.CryptographicStandard);