VB.NET

Sign a PDF using SmartCard or HSM (Hardware Security Module)

See more PDF Signatures Examples

This example demonstrates how to a sign a PDF using a smartcard or HSM (hardware security module).

Note: This example requires Chilkat v9.5.0.88 or greater.

VB.NET

Dim success As Boolean = False

' 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 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.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


' Options for signing are specified in JSON.
Dim json As New Chilkat.JsonObject

' In most cases, the signingCertificateV2 and signingTime attributes are required.
json.UpdateInt("signingCertificateV2",1)
json.UpdateInt("signingTime",1)

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

' Use a font scale of 10.0
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.
json.UpdateString("appearance.text[0]","Digitally signed by: cert_cn")
json.UpdateString("appearance.text[1]","current_dt")
json.UpdateString("appearance.text[2]","The crazy brown fox jumps over the lazy dog.")

' Use a certificate on a smartcard or USB token.
Dim cert As New Chilkat.Cert

' Provide the smartcard PIN.
' Set the smartcard PIN prior to calling LoadFromSmartcard.
' If the PIN is not explicitly provided here, the Windows OS should
' display a dialog for the PIN.
cert.SmartCardPin = "123456"

' Load the certificate on the smartcard currently in the reader (or on the USB token).
' Pass an empty string to allow Chilkat to automatically choose the CSP (Cryptographi Service Provider).
' See Load Certificate on Smartcard for information about explicitly selecting a particular CSP.
success = cert.LoadFromSmartcard("")
If (success = False) Then
    Debug.WriteLine(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.WriteLine(pdf.LastErrorText)
    Exit Sub
End If


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


Debug.WriteLine("The PDF has been successfully cryptographically signed using an HSM.")