(PHP Extension) 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).

Note: This example requires Chilkat v9.5.0.85 or greater.

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

// 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);

// 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->UpdateBool('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->UpdateBool('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->UpdateString('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->UpdateString('timestampToken.tsaUsername','the_tsa_username');
$json->UpdateString('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->UpdateBool('timestampToken.requestTsaCert',true);

// 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 with a TSA timestamp.');

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

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

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


?>