(VB.NET) Sign PDF in the Cloud using AWS CloudHSM

See more Signing in the Cloud Examples

Demonstrates how to sign a PDF using AWS CloudHSM. The signing of the hash happens on a hardware token in AWS CloudHSM. Everything else involving the updating the PDF to add the signature happens locally within Chilkat.

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

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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 Chilkat.Pkcs11

' Provide the path to the AWS CloudHSM PKCS11 driver.
' This example runs on Windows, so we'll provide the CloudHSM DLL.
' If your code runs on Linux, the CloudHSM driver might be at /opt/cloudhsm/lib/libcloudhsm_pkcs11.so
pkcs11.SharedLibPath = "C:\Program Files\Amazon\CloudHSM\lib\cloudhsm_pkcs11.dll"

' Your PIN should be a string containing your crypto user's login and password, with a colon char delimiting.
' See https://docs.aws.amazon.com/cloudhsm/latest/userguide/pkcs11-pin.html
Dim pin As String = "user:password"
Dim userType As Integer = 1

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



Dim cert As New Chilkat.Cert
success = cert.LoadFromFile("qa_data/certs/myCert.cer")
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    Exit Sub
End If


' Tell the certificate to link with the PKCS11 session.
' The cert's private key should be installed on the CloudHSM.
' If there are multiple private keys on the CloudHSM, then Chilkat will automatically
' locate and use the private key corresponding to the certificate.
success = cert.LinkPkcs11(pkcs11)
If (success = False) Then
    Debug.WriteLine(cert.LastErrorText)
    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 Chilkat.Pdf

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


Dim json As New Chilkat.JsonObject

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

Dim i As Integer = 0
json.I = i
json.UpdateString("appearance.text[i]","Digitaly signed by: Xyz Widgets, Inc.")
i = i + 1
json.I = i
json.UpdateString("appearance.text[i]","current_dt")
i = i + 1
json.I = i
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 = False) Then
    Debug.WriteLine(pdf.LastErrorText)
    success = pkcs11.CloseSession()
    Exit Sub
End If


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

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


Debug.WriteLine("Success.")