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Lua Requires Chilkat v9.5.0.85+

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.

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Lua 
local chilkat = require("chilkat")

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

local pdf = chilkat.Pdf.new()

-- Load a PDF to be signed.
-- The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
local success = pdf:load_file("qa_data/pdf/hello.pdf")
if not success then
    print(pdf.last_error_text)
    return
end

-- Options for signing are specified in JSON.
local json = chilkat.JsonObject.new()

-- In most cases, the signingCertificateV2 and signingTime attributes are required.
json:update_int("signingCertificateV2", 1)
json:update_int("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).
json:update_bool("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.
pdf.uncommon_options = "LOG_OCSP_HTTP,LOG_CRL_HTTP"

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

-- Load the signing certificate. (Use your own certificate.)
local cert = chilkat.Cert.new()
success = cert:load_pfx_file("qa_data/pfx/myPdfSigningCert.pfx", "pfxPassword")
if not success then
    print(cert.last_error_text)
    return
end

-- Tell the pdf object to use the certificate for signing.
success = pdf:set_signing_cert(cert)
if not success then
    print(pdf.last_error_text)
    return
end

success = pdf:sign_pdf(json, "qa_output/hello_ltv_signed.pdf")
if not success then
    print(pdf.last_error_text)
    return
end

print("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