(Excel) Sign a PDF using Certificate from Windows Certificate Store

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This example demonstrates how to a sign a PDF using a certificate from the Windows Certificate Store.

Note: This example requires Chilkat v9.5.0.85 or greater.

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

Dim pdf As Chilkat.Pdf
Set pdf = Chilkat.NewPdf

' Load a PDF to be signed.
' The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf

success = pdf.LoadFile("qa_data/pdf/hello.pdf")
If (success = False) Then
    Debug.Print pdf.LastErrorText
    Exit Sub
End If

' Options for signing are specified in JSON.
Dim json As Chilkat.JsonObject
Set json = Chilkat.NewJsonObject

' In most cases, the signingCertificateV2 and signingTime attributes are required.
Dim success As Boolean
success = json.UpdateInt("signingCertificateV2",1)
success = json.UpdateInt("signingTime",1)

' Put the signature on page 1, top left
success = json.UpdateInt("page",1)
success = json.UpdateString("appearance.y","top")
success = json.UpdateString("appearance.x","left")

' Use a font scale of 10.0
success = json.UpdateString("appearance.fontScale","10.0")

' In this example, the appearance of the digital signature will contain three lines:
' 1) The signing certificate's common name
' 2) The current date/time
' 3) Some arbitrary text.
' The keyword "cert_cn" is replaced with the Certificate's Subject Common Name.
' The keyword "current_dt" is replaced with the current date/time.
' Any number of appearance text lines can be added.
success = json.UpdateString("appearance.text[0]","Digitally signed by: cert_cn")
success = json.UpdateString("appearance.text[1]","current_dt")
success = json.UpdateString("appearance.text[2]","The crazy brown fox jumps over the lazy dog.")

' Load a certificate by specifying the common name ("CN" part of the certificate's Subject)
Dim cert As Chilkat.Cert
Set cert = Chilkat.NewCert
success = cert.LoadByCommonName("Xyz Widgets, Inc.")
If (success = False) Then
    Debug.Print cert.LastErrorText
    Exit Sub
End If

' Tell the pdf object to use the certificate for signing.
success = pdf.SetSigningCert(cert)
If (success = False) Then
    Debug.Print pdf.LastErrorText
    Exit Sub
End If

success = pdf.SignPdf(json,"qa_output/hello_signed.pdf")
If (success = False) Then
    Debug.Print pdf.LastErrorText
    Exit Sub
End If

Debug.Print "The PDF has been successfully cryptographically signed."