PowerBuilder

PDF Sign Under Existing Signature

See more PDF Signatures Examples

This example explains how sign a previously-signed PDF and place the signature appearance below the existing signature.

Note: This example requires Chilkat v9.5.0.85 or greater.

PowerBuilder

integer li_rc
integer li_Success
oleobject loo_Pdf
oleobject loo_Json
oleobject loo_Cert

li_Success = 0

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

loo_Pdf = create oleobject
li_rc = loo_Pdf.ConnectToNewObject("Chilkat.Pdf")
if li_rc < 0 then
    destroy loo_Pdf
    MessageBox("Error","Connecting to COM object failed")
    return
end if

// Load a PDF to be signed.
li_Success = loo_Pdf.LoadFile("qa_data/pdf/sign_testing_4/hello_signed.pdf")
if li_Success = 0 then
    Write-Debug loo_Pdf.LastErrorText
    destroy loo_Pdf
    return
end if

// The PDF we'll be signing already has a signature added in Adobe Acrobat DC.
// It looks like this:
// (Notice the Adobe background logo, which is commonly what you'll see when a signature
// is created by Adobe Acrobat.  Chilkat (obviously) does not create signatures using the Adobe
// logo because it would be a copyright violation.)

// (image:https://example-code.com/images/signed_once_with_adobe_acrobat.jpg/endImage)

// Options for signing are specified in JSON.
loo_Json = create oleobject
li_rc = loo_Json.ConnectToNewObject("Chilkat.JsonObject")

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

// To put our new signature underneath the existing signature, we have to specify the page
// where the existing signature is found, and then we can specify "under" for the "appearance.y"
loo_Json.UpdateInt("page",1)
loo_Json.UpdateString("appearance.y","under")

loo_Json.UpdateString("appearance.fontScale","10.0")

loo_Json.UpdateString("appearance.text[0]","Reason: Agreement Accepted by John")
loo_Json.UpdateString("appearance.text[1]","Date: current_dt")

// Load the signing certificate. (Use your own certificate.)
loo_Cert = create oleobject
li_rc = loo_Cert.ConnectToNewObject("Chilkat.Cert")

li_Success = loo_Cert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","secret")
if li_Success = 0 then
    Write-Debug loo_Cert.LastErrorText
    destroy loo_Pdf
    destroy loo_Json
    destroy loo_Cert
    return
end if

// Tell the pdf object to use the certificate for signing.
li_Success = loo_Pdf.SetSigningCert(loo_Cert)
if li_Success = 0 then
    Write-Debug loo_Pdf.LastErrorText
    destroy loo_Pdf
    destroy loo_Json
    destroy loo_Cert
    return
end if

// Note: When adding an additional signature to a PDF, the existing signatures
// are validated, and this includes validating the certificates previously used to 
// create the existing signatures.  (A signature typically embeds the signing certs.)
// In some cases, the certificates and/or certs in the chain of authentication for 
// existing signatures are not present, and are not available on the current system.
// In this case, you can skip the validation by setting this keyword in UncommonOptions:
loo_Pdf.UncommonOptions = "NO_VERIFY_CERT_SIGNATURES"

li_Success = loo_Pdf.SignPdf(loo_Json,"qa_output/hello_signed.pdf")
if li_Success = 0 then
    Write-Debug loo_Pdf.LastErrorText
    destroy loo_Pdf
    destroy loo_Json
    destroy loo_Cert
    return
end if

Write-Debug "The PDF has been successfully cryptographically signed."

// Here's a screenshot of the 2nd signature positioned under the 1st in Adobe Acrobat:

// (image:https://example-code.com/images/signed_under_existing_signature.jpg/endImage)


destroy loo_Pdf
destroy loo_Json
destroy loo_Cert