(VB.NET) 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.)
Dim cert As New Chilkat.Cert
Dim success As Boolean = cert.LoadByThumbprint("ea5a129c1919a52d238ee28d9f3a8f345b768388","hex")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Found: " & cert.SubjectDN)

' First export the private key the easy way.
Dim privKey As Chilkat.PrivateKey = cert.ExportPrivateKey()
If (cert.LastMethodSuccess = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


' 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.)
' 

Dim storageProvider As String = cert.CspName
Dim keyName As String = 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.
Dim keyCon As New Chilkat.KeyContainer
Dim privKey2 As New Chilkat.PrivateKey
Dim silentFlag As Boolean = False
success = keyCon.ExportKey(keyName,storageProvider,silentFlag,privKey2)
If (success = False) Then
    Debug.WriteLine(keyCon.LastErrorText)
    Exit Sub
End If


' 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) Then
    Debug.WriteLine(privKey2.LastErrorText)
    Exit Sub
End If


Debug.WriteLine("Success.")