(VB.NET) Get PDF Signer Certs

See more PDF Signatures Examples

This example demonstrates how to validate the signatures in a PDF and also shows how to get each signature's signer certificate.

Note: This example requires Chilkat v9.5.0.87 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 New Chilkat.Pdf

' Load a PDF that has cryptographic signatures to be validated
Dim success As Boolean = pdf.LoadFile("qa_data/pdf/sign_testing_1/helloSigned2.pdf")
If (success = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


' Each time we verify a signature, information about the signature is written into
' sigInfo (replacing whatever sigInfo previously contained).
Dim sigInfo As New Chilkat.JsonObject

' Iterate over each signature and validate each.
Dim numSignatures As Integer = pdf.NumSignatures
Dim validated As Boolean = False
Dim cert As New Chilkat.Cert
Dim i As Integer = 0
While i < numSignatures
    validated = pdf.VerifySignature(i,sigInfo)
    Debug.WriteLine("Signature " & i & " validated: " & validated)

    ' The GetSignerCert method was added in Chilkat v9.5.0.87
    ' After calling VerifySignature, you can get the signer certificate by calling
    ' GetSignerCert with the same index. 
    success = pdf.GetSignerCert(i,cert)
    If (success <> False) Then
        Debug.WriteLine("PDF signer certificate: " & cert.SubjectDN)
    End If


    i = i + 1
End While

Debug.WriteLine("Finished.")