SSL on Self Hosting Web API RRS feed

  • Question

  • Hi All,

    I have been having some trouble getting SSL enabled for my self hosting web api.

    I have been trying with the code below, but if there is a better way of doing this, i would like to know :) 

    I use this code to generate the cert and register it against a port:

    public static X509Certificate2 GenerateCert(string certName, TimeSpan expiresIn)
                var store = new X509Store(StoreName.Root, StoreLocation.LocalMachine);
                var existingCert = store.Certificates.Find(X509FindType.FindBySubjectName, certName, false);
                if (existingCert.Count > 0)
                    return existingCert[0];
                    var cert = CreateSelfSignedCertificate(certName, expiresIn);
                    return cert;
            public static void RegisterSslOnPort(int port, string certThumbprint)
                var appId = Guid.NewGuid();
                string arguments = $"http add sslcert ipport={port} certhash={certThumbprint} appid={{{appId}}}";
                ProcessStartInfo procStartInfo = new ProcessStartInfo("netsh", arguments);
                procStartInfo.RedirectStandardOutput = true;
                procStartInfo.UseShellExecute = false;
                procStartInfo.CreateNoWindow = true;
                var process = Process.Start(procStartInfo);
                while (!process.StandardOutput.EndOfStream)
                    string line = process.StandardOutput.ReadLine();
            public static X509Certificate2 CreateSelfSignedCertificate(string subjectName, TimeSpan expiresIn)
                // create DN for subject and issuer
                var dn = new CX500DistinguishedName();
                dn.Encode("CN=" + subjectName, X500NameFlags.XCN_CERT_NAME_STR_NONE);
                // create a new private key for the certificate
                CX509PrivateKey privateKey = new CX509PrivateKey();
                privateKey.ProviderName = "Microsoft Base Cryptographic Provider v1.0";
                privateKey.MachineContext = true;
                privateKey.Length = 2048;
                privateKey.KeySpec = X509KeySpec.XCN_AT_SIGNATURE; // use is not limited
                privateKey.ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_PLAINTEXT_EXPORT_FLAG;
                // Use the stronger SHA512 hashing algorithm
                var hashobj = new CObjectId();
                    AlgorithmFlags.AlgorithmFlagsNone, "SHA512");
                // add extended key usage if you want - look at MSDN for a list of possible OIDs
                var oid = new CObjectId();
                oid.InitializeFromValue(""); // SSL server
                var oidlist = new CObjectIds();
                var eku = new CX509ExtensionEnhancedKeyUsage();
                // Create the self signing request
                var cert = new CX509CertificateRequestCertificate();
                cert.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextMachine, privateKey, "");
                cert.Subject = dn;
                cert.Issuer = dn; // the issuer and the subject are the same
                cert.NotBefore = DateTime.Now;
                // this cert expires immediately. Change to whatever makes sense for you
                cert.NotAfter = DateTime.Now.Add(expiresIn);
                cert.X509Extensions.Add((CX509Extension)eku); // add the EKU
                cert.HashAlgorithm = hashobj; // Specify the hashing algorithm
                cert.Encode(); // encode the certificate
                // Do the final enrollment process
                var enroll = new CX509Enrollment();
                enroll.InitializeFromRequest(cert); // load the certificate
                enroll.CertificateFriendlyName = subjectName; // Optional: add a friendly name
                string csr = enroll.CreateRequest(); // Output the request in base64
                // and install it back as the response
                    csr, EncodingType.XCN_CRYPT_STRING_BASE64, ""); // no password
                // output a base64 encoded PKCS#12 so we can import it back to the .Net security classes
                var base64encoded = enroll.CreatePFX("", // no password, this is for internal consumption
                // instantiate the target class with the PKCS#12 data (and the empty password)
                return new System.Security.Cryptography.X509Certificates.X509Certificate2(
                    System.Convert.FromBase64String(base64encoded), "",
                    // mark the private key as exportable (this is usually what you want to do)

    I call this code from:

     private static void SetUpWebApi()
                    Trace.WriteLine("Setting up web service on " + appsettings.ApiUrl);
                    var certSubjectName = "TestCert";
                    var expiresIn = TimeSpan.FromDays(7);
                    var cert = Cert.RegisterCertificate.GenerateCert(certSubjectName, expiresIn);
                    Console.WriteLine("Generated certificate, {0}Thumbprint: {1}{0}", Environment.NewLine, cert.Thumbprint);
                    Cert.RegisterCertificate.RegisterSslOnPort(9822, cert.Thumbprint);
                    Console.WriteLine($"Registerd SSL on port: {9822}");
                    string url = appsettings.ApiUrl.Replace("http", "https");
                    Trace.WriteLine($"Web service started at: {DateTime.UtcNow:D}  at Url: {url}");
                catch (Exception ex)

    When i first start up my app on port 9822 and load in the following URL https://localhost:9822/api/system/connecttest I get the following  

    On image 3 it states the SSL cert is invalid, but on the last image it states the cert is ok.

    Any ideas as to what I am doing wrong here?



    Friday, February 15, 2019 12:36 PM

All replies

  • The cert is valid as far as certs go, but it doesn't chain to a trusted root CA.

    This posting is provided "AS IS" with no warranties, and confers no rights.

    Friday, March 22, 2019 4:57 PM
  • Hi,

    sorry for the late response, how do I how do I chain to a trusted root CA?



    Wednesday, February 26, 2020 11:49 AM