Need help on FTPS transfer using X509 Certificates

Question

I am developing a FTPS component in my ASP.Net application.
We configued the Personal Certificate,Intermediate Certificate and Root Certificate in Server and Client machine MMC console.
I am stuck in to implement the same as I am getting below error when the the line "using (Stream writer = ftpRequest.GetRequestStream())" is getting executed.
System.Net Information: 0 : [6876] SecureChannel#65124268 - Certificate is of type X509Certificate2 and contains the private key.
System.Net Information: 0 : [6876] AcquireCredentialsHandle(package = Microsoft Unified Security Protocol Provider, intent = Outbound, scc = System.Net.SecureCredential)
System.Net Error: 0 : [6876] AcquireCredentialsHandle() failed with error 0X8009030D.
System.Net Information: 0 : [6876] AcquireCredentialsHandle(package = Microsoft Unified Security Protocol Provider, intent = Outbound, scc = System.Net.SecureCredential)
System.Net Error: 0 : [6876] AcquireCredentialsHandle() failed with error 0X8009030D.
System.Net.Sockets Verbose: 0 : [6876] Socket#19949373::Dispose()
System.Net Information: 0 : [6876] FtpWebRequest#64456428::(Releasing FTP connection#53218812.)
System.Net Error: 0 : [6876] Exception in FtpWebRequest#64456428::GetRequestStream - The remote server returned an error: 234 SecurFTP: SSL starting
at System.Net.FtpWebRequest.CheckError()
at System.Net.FtpWebRequest.SyncRequestCallback(Object obj)
at System.IO.Stream.Close()
at System.Net.ConnectionPool.Destroy(PooledStream pooledStream)
at System.Net.ConnectionPool.PutConnection(PooledStream pooledStream, Object owningObject, Int32 creationTimeout, Boolean canReuse)
at System.Net.FtpWebRequest.FinishRequestStage(RequestStage stage)
at System.Net.FtpWebRequest.GetRequestStream()
System.Net Verbose: 0 : [6876] Exiting FtpWebRequest#64456428::GetRequestStream()
System.Net Information: 0 : [1320] ServicePoint#797974 - Closed as idle.
Please help me to solve this issue as it is urgent.
Below is my sample code:
public bool FileTransferStatus(FileInfo oFile, string localCertificateNames, bool isFileType, out string statusMessage)
FtpWebRequest ftpRequest;
FtpWebResponse ftpResponse;
try
ftpRequest = (FtpWebRequest)FtpWebRequest.Create(FTPSite + CurrentDirectory + oFile.Name);
ftpRequest.Method = WebRequestMethods.Ftp.UploadFile;
ftpRequest.Proxy = null;
ftpRequest.UseBinary = true;
ftpRequest.Credentials = new NetworkCredential(UserName, Password);
ftpRequest.KeepAlive = KeepAlive;
ftpRequest.EnableSsl = UseSSL;
ftpRequest.UsePassive = true;
if (UseSSL)
ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(ValidateServerCertificate);
List<string> listLocalCertificates = localCertificateNames.Split(',').ToList<string>();
if (isFileType)
foreach (string localCertificate in listLocalCertificates)
string currentCertificate = localCertificate.Replace("\n", "").Replace("\t", "").Replace("\r", "");
X509Certificate certificate = X509Certificate.CreateFromCertFile(System.AppDomain.CurrentDomain.BaseDirectory + currentCertificate.Trim());
ftpRequest.ClientCertificates.Add(certificate);
else
X509Store storeRoot = new X509Store(StoreName.Root, StoreLocation.LocalMachine);
storeRoot.Open(OpenFlags.ReadOnly);
X509Store storePersonal = new X509Store(StoreName.My, StoreLocation.LocalMachine);
storePersonal.Open(OpenFlags.ReadOnly);
List<string> listSerialNumbers = localCertificateNames.Split(',').ToList<string>();
foreach (string sn in listSerialNumbers)
string serialNumber = sn.Trim().ToUpper();
X509CertificateCollection certificates = storeRoot.Certificates.Find(X509FindType.FindBySerialNumber, serialNumber, false);
if (certificates.Count == 0) // Not in root store
certificates = storePersonal.Certificates.Find(X509FindType.FindBySerialNumber, serialNumber, true);
if (certificates.Count == 0) //Not in personal store
throw new Exception(string.Format("Certificate {0} not found", serialNumber));
storeRoot.Close();
storePersonal.Close();
X509Certificate certificate = certificates[0];
ftpRequest.ClientCertificates.Add(certificate);
//Selection of file to be uploaded
byte[] fileContents = new byte[oFile.Length];
using (FileStream fr = oFile.OpenRead())
fr.Read(fileContents, 0, Convert.ToInt32(oFile.Length));
using (Stream writer = ftpRequest.GetRequestStream())
writer.Write(fileContents, 0, fileContents.Length);
//Gets the FtpWebResponse of the uploading operation
ftpResponse = (FtpWebResponse)ftpRequest.GetResponse();
ftpResponse.Close();
ftpRequest = null;
statusMessage = "Uploaded successfully";
return true;
catch (Exception webex)
statusMessage = webex.Message;
return false;

Answer 1

Hi,
In .NET, you have built-in support for FTPS in the .NET Framework (see the FtpWebRequest class). However, functionality of this class is severely limited, especially in the SSL/TLS control aspect. The .NET Framework doesn't include any support for SSH or
SFTP.
In VCL, you have a selection of free components and libraries that provide FTP functionality. When you add OpenSSL to them, you can get FTPS for free. If you don't want to deal with OpenSSL DLLs, you can use one of the commercially available libraries for
SSL and FTPS support. Again, there are no freeware SFTP components available for .NET.
Mark as answer or vote as helpful if you find it useful | Ammar Zaied [MCP]