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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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Dim success As Boolean = False

'  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 ChilkatPkcs11
pkcs11.Initialize

'  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 Int = 1

'  Establish a PKCS logged-on session using the driver (.so, .dylib, or .dll) as specified in the SharedLibPath above.
success = pkcs11.QuickSession(userType, pin)
If success = False Then
    Log(pkcs11.LastErrorText)
    Return
End If


Dim cert As ChilkatCert
cert.Initialize("cert")
success = cert.LoadFromFile("qa_data/certs/myCert.cer")
If success = False Then
    Log(cert.LastErrorText)
    Return
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
    Log(cert.LastErrorText)
    Return
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 ChilkatPdf
pdf.Initialize("pdf")

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


Dim json As ChilkatJsonObject
json.Initialize

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 Int = 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
    Log(pdf.LastErrorText)
    success = pkcs11.CloseSession
    Return
End If


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

'  Revert to an unauthenticated session by calling Logout.
success = pkcs11.Logout
If success = False Then
    Log(pkcs11.LastErrorText)
    success = pkcs11.CloseSession
    Return
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
    Log(pkcs11.LastErrorText)
    Return
End If


Log("Success.")