Visual FoxPro

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.

Visual FoxPro

LOCAL lnSuccess
LOCAL loPkcs11
LOCAL lcPin
LOCAL lnUserType
LOCAL loCert
LOCAL loPdf
LOCAL loJson
LOCAL i

lnSuccess = 0

* 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.

loPkcs11 = CreateObject('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
loPkcs11.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
lcPin = "user:password"
lnUserType = 1

* Establish a PKCS logged-on session using the driver (.so, .dylib, or .dll) as specified in the SharedLibPath above.
lnSuccess = loPkcs11.QuickSession(lnUserType,lcPin)
IF (lnSuccess = 0) THEN
    ? loPkcs11.LastErrorText
    RELEASE loPkcs11
    CANCEL
ENDIF

loCert = CreateObject('Chilkat.Cert')
lnSuccess = loCert.LoadFromFile("qa_data/certs/myCert.cer")
IF (lnSuccess = 0) THEN
    ? loCert.LastErrorText
    RELEASE loPkcs11
    RELEASE loCert
    CANCEL
ENDIF

* 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.
lnSuccess = loCert.LinkPkcs11(loPkcs11)
IF (lnSuccess = 0) THEN
    ? loCert.LastErrorText
    RELEASE loPkcs11
    RELEASE loCert
    CANCEL
ENDIF

* --------------------------------------------------------------------------
* 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..

loPdf = CreateObject('Chilkat.Pdf')

* Load a PDF to be signed.
lnSuccess = loPdf.LoadFile("qa_data/pdf/hello.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf.LastErrorText
    lnSuccess = loPkcs11.CloseSession()
    RELEASE loPkcs11
    RELEASE loCert
    RELEASE loPdf
    CANCEL
ENDIF

loJson = CreateObject('Chilkat.JsonObject')

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

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

* The certificate is internally linked to the Pkcs11 object, which is currently in an authenticated session.
lnSuccess = loPdf.SetSigningCert(loCert)

lnSuccess = loPdf.SignPdf(loJson,"qa_output/out.pdf")
IF (lnSuccess = 0) THEN
    ? loPdf.LastErrorText
    lnSuccess = loPkcs11.CloseSession()
    RELEASE loPkcs11
    RELEASE loCert
    RELEASE loPdf
    RELEASE loJson
    CANCEL
ENDIF

* --------------------------------------------------------------------------

* Revert to an unauthenticated session by calling Logout.
lnSuccess = loPkcs11.Logout()
IF (lnSuccess = 0) THEN
    ? loPkcs11.LastErrorText
    lnSuccess = loPkcs11.CloseSession()
    RELEASE loPkcs11
    RELEASE loCert
    RELEASE loPdf
    RELEASE loJson
    CANCEL
ENDIF

* When finished, close the session.
* It is important to close the session (memory leaks will occur if the session is not properly closed).
lnSuccess = loPkcs11.CloseSession()
IF (lnSuccess = 0) THEN
    ? loPkcs11.LastErrorText
    RELEASE loPkcs11
    RELEASE loCert
    RELEASE loPdf
    RELEASE loJson
    CANCEL
ENDIF

? "Success."

RELEASE loPkcs11
RELEASE loCert
RELEASE loPdf
RELEASE loJson