Lianja

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.

Lianja

llSuccess = .F.

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

loPdf = createobject("CkPdf")

// Load a PDF to be signed.
// The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
llSuccess = loPdf.LoadFile("qa_data/pdf/hello.pdf")
if (llSuccess = .F.) then
    ? loPdf.LastErrorText
    release loPdf
    return
endif

// Options for signing are specified in JSON.
loJson = createobject("CkJsonObject")

// In most cases, the signingCertificateV2 and signingTime attributes are required.
loJson.UpdateInt("signingCertificateV2",1)
loJson.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).
loJson.UpdateBool("ltvOcsp",.T.)

// -----------------------------------------------------------------------------------
// 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.
loPdf.UncommonOptions = "LOG_OCSP_HTTP,LOG_CRL_HTTP"

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

// Load the signing certificate. (Use your own certificate.)
loCert = createobject("CkCert")
llSuccess = loCert.LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","pfxPassword")
if (llSuccess = .F.) then
    ? loCert.LastErrorText
    release loPdf
    release loJson
    release loCert
    return
endif

// Tell the pdf object to use the certificate for signing.
llSuccess = loPdf.SetSigningCert(loCert)
if (llSuccess = .F.) then
    ? loPdf.LastErrorText
    release loPdf
    release loJson
    release loCert
    return
endif

llSuccess = loPdf.SignPdf(loJson,"qa_output/hello_ltv_signed.pdf")
if (llSuccess = .F.) then
    ? loPdf.LastErrorText
    release loPdf
    release loJson
    release loCert
    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)


release loPdf
release loJson
release loCert