(Delphi ActiveX) 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.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
cert: TChilkatCert;
success: Integer;
privKey: IPrivateKey;
storageProvider: WideString;
keyName: WideString;
keyCon: TChilkatKeyContainer;
privKey2: TPrivateKey;
silentFlag: Integer;

begin
// 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.)
cert := TChilkatCert.Create(Self);
success := cert.LoadByThumbprint('ea5a129c1919a52d238ee28d9f3a8f345b768388','hex');
if (success = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Found: ' + cert.SubjectDN);

// First export the private key the easy way.
privKey := cert.ExportPrivateKey();
if (cert.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

// 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.)
// 

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

Memo1.Lines.Add('Information about the certificate''s private key:');
Memo1.Lines.Add('Storage Provider: ' + storageProvider);
Memo1.Lines.Add('Key Name: ' + keyName);

// Export using just the name of the storage provider and key.
keyCon := TChilkatKeyContainer.Create(Self);
privKey2 := TPrivateKey.Create(Self);
silentFlag := 0;
success := keyCon.ExportKey(keyName,storageProvider,silentFlag,privKey2.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(keyCon.LastErrorText);
    Exit;
  end;

// 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 = 0) then
  begin
    Memo1.Lines.Add(privKey2.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('Success.');
end;