(Visual Basic 6.0) PKCS11 Sign PDF using Certificate and Private Key on Smart Card / USB Token

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Sample code showing how to use PKCS11 to sign a PDF with a certificate and private key stored on a smart card or USB token.

Note: This example requires Chilkat v9.5.0.96 or later.

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

' Note: Chilkat's PKCS11 implementation runs on Windows, Linux, Mac OS X, and other supported operating systems.

Dim pkcs11 As New ChilkatPkcs11

pkcs11.SharedLibPath = "C:/Program Files (x86)/Gemalto/IDGo 800 PKCS#11/IDPrimePKCS1164.dll"
Dim pin As String
pin = "0000"
Dim userType As Long
userType = 1

' Establish a PKCS11 logged-on session using the driver (.so, .dylib, or .dll) as specified in the SharedLibPath above.
Dim success As Long
success = pkcs11.QuickSession(userType,pin)
If (success = 0) Then
    Debug.Print pkcs11.LastErrorText
    Exit Sub
End If

' Get the certificate (on the smart card) that has a private key.
' There are other ways to locate a certificate on the HSM.
' This example assumes there is a single certificate w/ private key.
Dim cert As New ChilkatCert
success = pkcs11.FindCert("privateKey","",cert)
If (success = 1) Then
    Debug.Print "Cert with private key: " & cert.SubjectCN
Else
    Debug.Print "No certificates having a private key were found."
    success = pkcs11.CloseSession()
    Exit Sub
End If

' --------------------------------------------------------------------------
' At this point, we have the cert to be used for signing.
' Our PDF signing code is the same as for a cert obtained from any other source..

Dim pdf As New ChilkatPdf

' Load a PDF to be signed.
success = pdf.LoadFile("qa_data/pdf/hello.pdf")
If (success = 0) Then
    Debug.Print pdf.LastErrorText
    success = pkcs11.CloseSession()
    Exit Sub
End If

Dim json As New ChilkatJsonObject

success = json.UpdateInt("page",1)
success = json.UpdateString("appearance.y","top")
success = json.UpdateString("appearance.x","left")
success = json.UpdateString("appearance.fontScale","10.0")
success = json.UpdateString("signingAlgorithm","pss")
success = json.UpdateString("hashAlgorithm","sha256")

Dim i As Long
i = 0
json.I = i
success = json.UpdateString("appearance.text[i]","Digitaly signed by: Xyz Widgets, Inc.")
i = i + 1
json.I = i
success = json.UpdateString("appearance.text[i]","current_dt")
i = i + 1
json.I = i
success = json.UpdateString("appearance.text[i]","blah blah blah")

' The certificate is internally linked to the Pkcs11 object, which is currently in an authenticated session.
success = pdf.SetSigningCert(cert)

success = pdf.SignPdf(json,"qa_output/out.pdf")
If (success = 0) Then
    Debug.Print pdf.LastErrorText
    success = pkcs11.CloseSession()
    Exit Sub
End If

' --------------------------------------------------------------------------

' Revert to an unauthenticated session by calling Logout.
success = pkcs11.Logout()
If (success = 0) Then
    Debug.Print pkcs11.LastErrorText
    success = pkcs11.CloseSession()
    Exit Sub
End If

' When finished, close the session.
' It is important to close the session (memory leaks will occur if the session is not properly closed).
success = pkcs11.CloseSession()
If (success = 0) Then
    Debug.Print pkcs11.LastErrorText
    Exit Sub
End If

Debug.Print "Success."