Perl

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.

Perl

use chilkat();

$success = 0;

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

$pdf = chilkat::CkPdf->new();

# Load a PDF to be signed.
# The "hello.pdf" is available at https://chilkatsoft.com/hello.pdf
$success = $pdf->LoadFile("qa_data/pdf/hello.pdf");
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

# Options for signing are specified in JSON.
$json = chilkat::CkJsonObject->new();

# In most cases, the signingCertificateV2 and signingTime attributes are required.
$json->UpdateInt("signingCertificateV2",1);
$json->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).
$json->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.
$pdf->put_UncommonOptions("LOG_OCSP_HTTP,LOG_CRL_HTTP");

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

# Load the signing certificate. (Use your own certificate.)
$cert = chilkat::CkCert->new();
$success = $cert->LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","pfxPassword");
if ($success == 0) {
    print $cert->lastErrorText() . "\r\n";
    exit;
}

# Tell the pdf object to use the certificate for signing.
$success = $pdf->SetSigningCert($cert);
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

$success = $pdf->SignPdf($json,"qa_output/hello_ltv_signed.pdf");
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

print "The PDF has been successfully cryptographically signed with long-term validation." . "\r\n";

# 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)