Xbase++

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.

Xbase++

LOCAL nSuccess
LOCAL oPdf
LOCAL oJson
LOCAL oCert

nSuccess := 0

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

oPdf := CreateObject("Chilkat.Pdf")

//  Load a PDF to be signed.
//  The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
nSuccess := oPdf:LoadFile("qa_data/pdf/hello.pdf")
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    RETURN
ENDIF

//  Options for signing are specified in JSON.
oJson := CreateObject("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", 1)

//  -----------------------------------------------------------------------------------
//  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 := CreateObject("Chilkat.Cert")
nSuccess := oCert:LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx", "pfxPassword")
IF (nSuccess == 0)
    ? oCert:LastErrorText
    oPdf:destroy()
    oJson:destroy()
    oCert:destroy()
    RETURN
ENDIF

//  Tell the pdf object to use the certificate for signing.
nSuccess := oPdf:SetSigningCert(oCert)
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oJson:destroy()
    oCert:destroy()
    RETURN
ENDIF

nSuccess := oPdf:SignPdf(oJson, "qa_output/hello_ltv_signed.pdf")
IF (nSuccess == 0)
    ? oPdf:LastErrorText
    oPdf:destroy()
    oJson:destroy()
    oCert:destroy()
    RETURN
ENDIF

? "The PDF has been successfully cryptographically signed with long-term validation."

//  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)

oPdf:destroy()
oJson:destroy()
oCert:destroy()