Xác minh chữ ký trong PDF qua .NET SDK

using Aspose.Pdf.Cloud.Sdk.Model;

namespace Signatures
{
    public class VerifySignatures
    {
        public static async Task Check(string documentName, string fieldName, string remoteFolder)
        {
		// Get your AppSid and AppSecret from https://dashboard.aspose.cloud (free registration required). 
		pdfApi = new PdfApi(AppSecret, AppSid);

                using (var file = File.OpenRead(Path.Combine(localFolder, documentName)))
		{ // Upload the local PDF to cloud storage folder name.
                    FilesUploadResult uploadResponse = await pdfApi.UploadFileAsync(Path.Combine(remoteFolder, documentName), documentName);
                    Console.WriteLine(uploadResponse.Uploaded[0]);
                }

                // Verify signatures in PDF via cloud storage.
                SignatureVerifyResponse response = await pdfApi.GetVerifySignatureAsync(documentName, fieldName, folder: remoteFolder);

                // Checks the response and logs the result.
                if (response == null)
                    Console.WriteLine("VerifySignatures(): Unexpected error!");
                else if (response.Code < 200 || response.Code > 299)
                    Console.WriteLine("VerifySignatures(): Failed to verify signatures in the document.");
                else
                { // Show signatures validation.
                    Console.WriteLine("VerifySignature(): Signature verified successfully in the Pdf document '{0}'. Status: '{1}'", 
                        documentName, response.Valid);
                }
            }
        }
    }