Check Certificate for Private Key

Checks to see if a certificate has its associated private key installed on the computer.

Detailed Instructions for Installing a PFX for Use by ASP / ASP.NET

Dim cert As New ChilkatCert

'  There are many ways of loading a Chilkat certificate object:
'  1) From a Windows registry-based certificate store.
'  2) From a PFX file.
'  3) From a DER encoded .cer file.
'  4) From a PEM file.

'  The point of this example is to show how to check for the existence
'  of a usable private key.  This is done by calling the HasPrivateKey method.

'  The LoadByCommonName method searches the registry-based
'  Windows Current User Certificate Store and Local Machine Certificate
'  Store for a certificate whose common name (CN) matches
'  the argument:
Dim success As Long
success = cert.LoadByCommonName("Chilkat Software, Inc.")
If (success = 0) Then
    MsgBox "Failed to find certificate!"
Else

    '  Display the certificate's distinguished name:
    Text1.Text = Text1.Text & cert.SubjectDN & vbCrLf

    Dim hasPrivKey As Long

    hasPrivKey = cert.HasPrivateKey()
    If (hasPrivKey = 1) Then
        Text1.Text = Text1.Text & "Certificate has a usable private key." & vbCrLf
    Else
        Text1.Text = Text1.Text & "Certificate does not have a private key." & vbCrLf
    End If

    '  If HasPrivateKey returns 0, it's possible that the private key
    '  does exist, but the calling process does not have permission to access it.

    '  If your program is running under IIS (perhaps in a web service), you need
    '  rights to the private key to perform a signature, and the IIS processes
    '  typically runs in the default IIS Application Pool under the
    '  NETWORK_SERVICE ID, which has no rights.

    '  Grant the ID Full Control rights to the private key which is stored in
    '  C:\Documents and Settings\All Users\Application Data\Microsoft\Crypto\RSA\Machine Keys.
    '  (Perhaps lesser rights would work; you may experiment).

End If

'  Alternatively, load a Certificate from a .cer file.
'  (Certs may also be loaded from other types of files, such as PEM, DER, PFX, etc.)
success = cert.LoadFromFile("myCert.cer")
If (success = 0) Then
    MsgBox "Failed to load certificate!"
Else

    hasPrivKey = cert.HasPrivateKey()
    If (hasPrivKey = 1) Then
        Text1.Text = Text1.Text & "Certificate has a usable private key." & vbCrLf
    Else
        Text1.Text = Text1.Text & "Certificate does not have a private key." & vbCrLf
    End If

End If