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Sign PDF with Long-Term Validation (LTV Enabled)

See more PDF Signatures Examples

This example demonstrates how to a sign a PDF with long-term validation (LTV) enabled.

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

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Local $bSuccess = False

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

$oPdf = ObjCreate("Chilkat.Pdf")

; Load a PDF to be signed.
; The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
$bSuccess = $oPdf.LoadFile("qa_data/pdf/hello.pdf")
If ($bSuccess = False) Then
    ConsoleWrite($oPdf.LastErrorText & @CRLF)
    Exit
EndIf

; Options for signing are specified in JSON.
$oJson = ObjCreate("Chilkat.JsonObject")

; In most cases, the signingCertificateV2 and signingTime attributes are required.
$oJson.UpdateInt("signingCertificateV2",1)
$oJson.UpdateInt("signingTime",1)

; Add the "ltvOcsp" instruction to the JSON passed to SignPdf.
; This is what causes Chilkat to create an LTV-enabled signature.
; 
; If we are signing a PDF that already has signatures, then the existing signatures
; are automatically verified, and Chilkat will do OCSP certificate status checking (if possible) 
; for those certs in existing signatures (including certs in the certificate chains) 
; that do not yet have a valid OCSP response in the DSS (Document Security Store).
; Chilkat will add the OCSP responses to the /OCSPs in the Document Security Store (/DSS).
; Also, and certificates from existing signatures not yet in the DSS are added to the /Certs 
; in the DSS.
; 
; Also, the "ltvOcsp" causes Chilkat to add the pdfRevocationInfoArchival authenticated attribute
; to the CMS signature.  The pdfRevocationInfoArchival attribute (1.2.840.113583.1.1.8)
; contains OCSP responses and the CRL for the issuer of the signing certificate.
; Therefore, Chilkat will send an OCSP request to the signing certificate's OCSP URl (if one exists)
; and will download the CRL from the issuer certificate's CRL Distribution Point (if one exists).
$oJson.UpdateBool("ltvOcsp",True)

; -----------------------------------------------------------------------------------
; Note: If Chilkat produces a signed PDF, but the signature is not LTV-enabled,
; the cause might be related to a failure to download CRL's or OCSP requests.
; See Possible Solution for Failure to Produce LTV-enabled PDF Signature
; -----------------------------------------------------------------------------------
; You can add the following to UncommonOptions to get detailed information about the CRL and OCSP requests
; You shouldn't set the following logging options unless there is a need, because it adds a large amount of information to the LastErrorText.
$oPdf.UncommonOptions = "LOG_OCSP_HTTP,LOG_CRL_HTTP"

; Define the appearance of the signature.
$oJson.UpdateInt("page",1)
$oJson.UpdateString("appearance.y","top")
$oJson.UpdateString("appearance.x","left")
$oJson.UpdateString("appearance.fontScale","10.0")
$oJson.UpdateString("appearance.text[0]","Digitally signed by: cert_cn")
$oJson.UpdateString("appearance.text[1]","current_dt")
$oJson.UpdateString("appearance.text[2]","This is an LTV-enabled signature.")

; Load the signing certificate. (Use your own certificate.)
$oCert = ObjCreate("Chilkat.Cert")
$bSuccess = $oCert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","pfxPassword")
If ($bSuccess = False) Then
    ConsoleWrite($oCert.LastErrorText & @CRLF)
    Exit
EndIf

; Tell the pdf object to use the certificate for signing.
$bSuccess = $oPdf.SetSigningCert($oCert)
If ($bSuccess = False) Then
    ConsoleWrite($oPdf.LastErrorText & @CRLF)
    Exit
EndIf

$bSuccess = $oPdf.SignPdf($oJson,"qa_output/hello_ltv_signed.pdf")
If ($bSuccess = False) Then
    ConsoleWrite($oPdf.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("The PDF has been successfully cryptographically signed with long-term validation." & @CRLF)

; If you open the Signature Panel in Adobe Acrobat, it will indicate that the signature is LTV enabled
; as shown here:
; (image:https://example-code.com/images/ltv_signature.jpg/endImage)