PHP Extension

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.

PHP Extension

<?php

include("chilkat.php");

$success = false;

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

$pdf = new CkPdf();

//  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 == false) {
    print $pdf->lastErrorText() . "\n";
    exit;
}

//  Options for signing are specified in JSON.
$json = new CkJsonObject();

//  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',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->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 = new CkCert();
$success = $cert->LoadPfxFile('qa_data/pfx/myPdfSigningCert.pfx','pfxPassword');
if ($success == false) {
    print $cert->lastErrorText() . "\n";
    exit;
}

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

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

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

//  If you open the Signature Panel in Adobe Acrobat, it will indicate that the signature is LTV enabled
//  as shown here:
//  

?>