(VB.NET) Download and Trust the DigiCert Global Root CA

Demonstrates how to download a root certificate and trust it.

For more information, see https://www.digicert.com/digicert-root-certificates.htm

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' This requires the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.

' In this example, the URLs for the DigiCert root CA certs are available at this web page:
' https://www.digicert.com/digicert-root-certificates.htm



' This example downloads the "DigiCert Global Root G3"
' Valid until: 15/Jan/2038
' Serial #: 05:55:56:BC:F2:5E:A4:35:35:C3:A4:0F:D5:AB:45:72
' Thumbprint: 7E04DE896A3E666D00E687D33FFAD93BE83D349E

Dim certUrl As String = "https://dl.cacerts.digicert.com/DigiCertGlobalRootG3.crt"

Dim http As New Chilkat.Http
Dim bdCert As New Chilkat.BinData
Dim success As Boolean = http.DownloadBd(certUrl,bdCert)
If (success = False) Then
    Debug.WriteLine(http.LastErrorText)
    Exit Sub
End If


' Load it into a Chilkat cert object.
Dim cert As New Chilkat.Cert
success = cert.LoadFromBd(bdCert)
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


' Examine the common name,serial, and thumbprint:
Debug.WriteLine("CN: " & cert.SubjectCN)
Debug.WriteLine("Serial: " & cert.SerialNumber)
Debug.WriteLine("Thumbprint: " & cert.Sha1Thumbprint)

' Output from the above:
' CN: DigiCert Global Root G3
' Serial: 055556BCF25EA43535C3A40FD5AB4572
' Thumbprint: 7E04DE896A3E666D00E687D33FFAD93BE83D349E

' If desired, the certificate can be saved to a local file so it does not need
' to be downloaded from the website every time.  
Dim certPath As String = "qa_data/certs/DigiCertGlobalRootG3.crt"
success = bdCert.WriteFile(certPath)

' To load the cert from a file...
success = cert.LoadFromFile(certPath)

' Do the following to add the cert to the collection of trusted roots
' for this application.  (Note:  The trust is not persisted.  Each time the
' application runs, it should load the cert (from whatever source, whether it is
' a file, a database,etc.) and do the following:
Dim troots As New Chilkat.TrustedRoots

troots.AddCert(cert)
troots.Activate()

Debug.WriteLine(cert.SubjectCN & " is now trusted for this run of this application.")