Lua Requires Chilkat v9.5.0.85+

Sign PDF with Timestamp from TSA (Timestamp Server Authority)

See more PDF Signatures Examples

This example demonstrates how to a sign a PDF that is both long-term validation (LTV) enabled and includes a validating timestamp from a TSA (Timestamp Server Authority). 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)

-- Tell Chilkat to create an LTV-enabled (long term validation) signature.
-- See PDF Long-Term Validation (LTV) Signature Example for more detailed comments about "ltvOcsp".
json:update_bool("ltvOcsp", true)

-- Tell Chilkat to request a timestamp from a TSA server and include the timestamp token (1.2.840.113549.1.9.16.2.14)
-- in the CMS signature's authentication attributes
json:update_bool("timestampToken.enabled", true)

-- In this example, we'll use a free TSA server (timestamp.digicert.com), but you may want to use your own timestamp authority server.
json:update_string("timestampToken.tsaUrl", "http://timestamp.digicert.com")

-- If the timestamp server requires a username/password, do the following.  Otherwise omit the following few lines of code.
json:update_string("timestampToken.tsaUsername", "the_tsa_username")
json:update_string("timestampToken.tsaPassword", "the_tsa_password")

-- When requesting the timestamp token, ask the server to include its certificate in the timestamp token response.
-- This allows for the timestamp server's certificate to be included in the LTV validation (i.e. if the timestamp server
-- has an OCSP URL, then Chilkat will also do the OCSP request for the timestamp server's certificate.)
json:update_bool("timestampToken.requestTsaCert", true)

-- 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 with a TSA timestamp.")

-- 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_with_timestamp.pdf")
if not success then
    print(pdf.last_error_text)
    return
end

print("The PDF has been successfully cryptographically signed with TSA timestamp and long-term validation.")

-- If you open the Signature Panel in Adobe Acrobat, it will indicate that the signature is LTV enabled
-- and contains an embedded timestamp:
--