(C#) Export a Private Key from an MS Storage Provider

Demonstrates how to export a private key from a Microsoft Storage Provider.

Note: This example requires Chilkat v9.5.0.83 or greater.

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// This example requires Chilkat v9.5.0.83 or greater.

// We'll export a certificate's private key from the MS storage provider.
// It is assumed the certificate + private key is already installed on the Windows system.
// The export does not remove the key from the Windows storage provider.

// First, let's get a certificate in one of the many ways we can do it.
// (I ran certmgr.msc, opened a certificate, and noted it's thumbprint.)
Chilkat.Cert cert = new Chilkat.Cert();
bool success = cert.LoadByThumbprint("ea5a129c1919a52d238ee28d9f3a8f345b768388","hex");
if (success == false) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

Debug.WriteLine("Found: " + cert.SubjectDN);

// First export the private key the easy way.
Chilkat.PrivateKey privKey = cert.ExportPrivateKey();
if (cert.LastMethodSuccess == false) {
    Debug.WriteLine(cert.LastErrorText);
    return;
}

// OK.. we have the private key.  Do whatever we want with it..

// -------------------------------------------------------------
// Now let's export in a more roundabout way by getting information about the 
// storage provider and key name and then we'll export completely independent
// of the certificate.
// 
// Remember: The private key is not contained within the certificate.  An X.509 certificate
// embeds the public key, but the counterpart private key is stored elsewhere, such
// as in a .pfx/.p12, or as in this case, in the Windows "protected store", or perhaps on
// a smartcard or hardware token.  (But a private key stored on a smartcard or token cannot
// be exported.  It must remain on the hardware.)
// 

string storageProvider = cert.CspName;
string keyName = cert.KeyContainerName;

Debug.WriteLine("Information about the certificate's private key:");
Debug.WriteLine("Storage Provider: " + storageProvider);
Debug.WriteLine("Key Name: " + keyName);

// Export using just the name of the storage provider and key.
Chilkat.KeyContainer keyCon = new Chilkat.KeyContainer();
Chilkat.PrivateKey privKey2 = new Chilkat.PrivateKey();
bool silentFlag = false;
success = keyCon.ExportKey(keyName,storageProvider,silentFlag,privKey2);
if (success == false) {
    Debug.WriteLine(keyCon.LastErrorText);
    return;
}

// OK.. we have the private key in privKey2.  Do whatever we want with it..
// Perhaps we save as encrypted PKCS8 PEM.
success = privKey2.SavePkcs8EncryptedPemFile("myPassword","qa_output/privKey2.pem");
if (success == false) {
    Debug.WriteLine(privKey2.LastErrorText);
    return;
}

Debug.WriteLine("Success.");