Perl

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). 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);

# 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",1);

# 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",1);

# 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",1);

# 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 = 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_with_timestamp.pdf");
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

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

# If you open the Signature Panel in Adobe Acrobat, it will indicate that the signature is LTV enabled
# and contains an embedded timestamp:
# (image:https://example-code.com/images/ltv_signature_with_timestamp.jpg/endImage)