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

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
cert: HCkCert;
success: Boolean;
privKey: HCkPrivateKey;
storageProvider: PWideChar;
keyName: PWideChar;
keyCon: HCkKeyContainer;
privKey2: HCkPrivateKey;
silentFlag: Boolean;

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 := CkCert_Create();
success := CkCert_LoadByThumbprint(cert,'ea5a129c1919a52d238ee28d9f3a8f345b768388','hex');
if (success = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

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

// First export the private key the easy way.
privKey := CkCert_ExportPrivateKey(cert);
if (CkCert_getLastMethodSuccess(cert) = False) then
  begin
    Memo1.Lines.Add(CkCert__lastErrorText(cert));
    Exit;
  end;

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

CkPrivateKey_Dispose(privKey);

// -------------------------------------------------------------
// 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 := CkCert__cspName(cert);
keyName := CkCert__keyContainerName(cert);

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 := CkKeyContainer_Create();
privKey2 := CkPrivateKey_Create();
silentFlag := False;
success := CkKeyContainer_ExportKey(keyCon,keyName,storageProvider,silentFlag,privKey2);
if (success = False) then
  begin
    Memo1.Lines.Add(CkKeyContainer__lastErrorText(keyCon));
    Exit;
  end;

// OK.. we have the private key in privKey2.  Do whatever we want with it..
// Perhaps we save as encrypted PKCS8 PEM.
success := CkPrivateKey_SavePkcs8EncryptedPemFile(privKey2,'myPassword','qa_output/privKey2.pem');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(privKey2));
    Exit;
  end;

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

CkCert_Dispose(cert);
CkKeyContainer_Dispose(keyCon);
CkPrivateKey_Dispose(privKey2);

end;