c# - "The credentials supplied to the package were not recognized" error when authenticating as server with certificate generated using BouncyCastle

Question

I'm trying to create a certificate using the BouncyCastle.Crypto dll, which is then used to authenticate a SslStream as the server in a Windows Service process, which runs under the Local System account.

However when I get to the SslStream.AuthenticateAsServer(certificate) call, it throws a Win32 exception with the error message "The credentials supplied to the package were not recognized".

There are several questions on here about this error message, but none of them seem to describe, or solve, my particular problem.

In the hope that someone may be able to offer some help, I include the code I am using to create and install the certificate:

// First create a certificate using the BouncyCastle classes
BigInteger serialNumber = BigInteger.ProbablePrime(120, new Random());
AsymmetricCipherKeyPair keyPair = GenerateKeyPair();

X509V1CertificateGenerator generator = new X509V1CertificateGenerator();
generator.SetSerialNumber(serialNumber);
generator.SetIssuerDN(new X509Name("CN=My Issuer"));
generator.SetNotBefore(DateTime.Today);
generator.SetNotAfter(DateTime.Today.AddYears(100));
generator.SetSubjectDN(new X509Name("CN=My Issuer"));
generator.SetPublicKey(keyPair.Public);
generator.SetSignatureAlgorithm("SHA1WITHRSA");

Org.BouncyCastle.X509.X509Certificate cert = generator.Generate(
    keyPair.Private, SecureRandom.GetInstance("SHA1PRNG"));

// Ok, now we have a BouncyCastle certificate, we need to convert it to the 
// System.Security.Cryptography class, by writing it out to disk and reloading
X509Certificate2 dotNetCert;

string tempStorePassword = "Password01"; // In real life I'd use a random password
FileInfo tempStoreFile = new FileInfo(Path.GetTempFileName());

try
{
    Pkcs12Store newStore = new Pkcs12Store();

    X509CertificateEntry entry = new X509CertificateEntry(cert);

    newStore.SetCertificateEntry(Environment.MachineName, entry);

    newStore.SetKeyEntry(
        Environment.MachineName,
        new AsymmetricKeyEntry(keyPair.Private),
        new [] { entry });

    using (FileStream s = tempStoreFile.Create())
    {
        newStore.Save(s, 
            tempStorePassword.ToCharArray(), 
            new SecureRandom(new CryptoApiRandomGenerator()));
    }

    // Reload the certificate from disk
    dotNetCert = new X509Certificate2(tempStoreFile.FullName, tempStorePassword);
}
finally
{
    tempStoreFile.Delete();
}

// Now install it into the required certificate stores
X509Store targetStore = new X509Store(StoreName.My, StoreLocation.LocalMachine);
targetStore.Open(OpenFlags.ReadWrite);
targetStore.Add(dotNetCert);
targetStore.Close();

Ok, now I have created and installed the certificate. I then configure my Windows Service to use this certificate by supplying it with the generated certificate's thumbprint. I then use the certificate like this:

// First load the certificate
X509Certificate2 certificate = null;

X509Store store = new X509Store(StoreName.My, StoreLocation.LocalMachine);
store.Open(OpenFlags.ReadOnly);

foreach (X509Certificate2 certInStore in store.Certificates)
{
    if (certInStore.Thumbprint == "...value not shown...")
    {
        certificate = certInStore;
        break;
    }
}

SslStream sslStream = new SslStream(new NetworkStream(socket, false), false);

// Now this line throws a Win32Exception 
// "The credentials supplied to the package were not recognized"
sslStream.AuthenticateAsServer(certificate);

Does anyone have any idea what the problem could be here?

I don't get the problem if I install a certificate created with 'makecert', but that isn't suitable for production certificates.

I've also tried creating a separate x509v1 CA certificate and then x509v3 certificate for server authentication, but I get the same error, so I removed this in the example code for simplicity.

Answer 1

That particular error message rings a bell. I'll guess that either you did not store the private key with the certificate, or, the Windows service does not have access to the private key. To check this, open the Certificates MMC snap-in:

1. Run mmc (e.g. from the Start menu)
2. File menu > Add/Remove Snap-in
3. Select "Certificates" in left pane and then click Add
4. Select "Computer Account" (for LocalMachine) then click Next, and then Finish

Navigate to the certificate and double-click in the right pane. On the General tab that comes up, you should see a little key icon at the bottom, along with the text, "You have a private key that corresponds to this certificate." If not, that's the problem. The private key was not saved.

If the private key is present, click Ok to dismiss this dialog, and then right-click on the certificate in the right pane and select on the pop-up menu: All Tasks > Manage Private Keys. In that dialog, make sure that the Windows account that the service runs under has read access to the private key. If it doesn't, that's the problem.

Edit: Oops, you wrote that the service runs as Local System, so it must be a missing private key, if it is one of these two problems. I'll leave the key access check in my answer anyway, for anybody else that hits this and is not running as Local System.