Perl Requires Chilkat v11.7.0+

Encrypt and Sign a PDF, and Sign an Encrypted PDF

See more PDF Protection Examples

Demonstrates signing together with encryption. A pending encrypt is applied by SignPdf before it signs, so one call produces a PDF that is both encrypted and signed. A PDF that is already encrypted can be signed too, and stays encrypted. When it was opened with only the user password its permissions decide: adding a signature field needs both the modify and the annotate permission. Loading the PDF with its owner password lifts that. Perl

use chilkat();

$success = 0;

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

#  The PDF used in this example is available at two_page_memo.pdf

#  The signing certificate, with its private key.
$cert = chilkat::CkCert->new();
$success = $cert->LoadPfxFile("qa_data/pfx/myPdfSigningCert.pfx","secret");
if ($success == 0) {
    print $cert->lastErrorText() . "\r\n";
    exit;
}

$pdf = chilkat::CkPdf->new();
$success = $pdf->LoadFile("qa_data/pdf/two_page_memo.pdf");
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

#  Encrypt with AES-256 and do not permit modifying.
$pdf->put_UserPassword("user-secret");
$pdf->put_OwnerPassword("owner-secret");
$json = chilkat::CkJsonObject->new();
$json->UpdateBool("permissions.modify",0);
$jsonOut = chilkat::CkJsonObject->new();
$success = $pdf->Protection("encrypt",$json,$jsonOut);
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

#  The encryption is still pending.  SignPdf applies it first and signs the encrypted result.
$success = $pdf->SetSigningCert($cert);
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

$sigOpts = chilkat::CkJsonObject->new();
$sigOpts->UpdateBool("invisibleSignature",1);
$sigOpts->UpdateInt("signingCertificateV2",1);
$sigOpts->UpdateInt("signingTime",1);
$success = $pdf->SignPdf($sigOpts,"qa_output/memo_encrypted_signed.pdf");
if ($success == 0) {
    print $pdf->lastErrorText() . "\r\n";
    exit;
}

#  The result is encrypted and signed.
$check = chilkat::CkPdf->new();
$check->put_UserPassword("user-secret");
$success = $check->LoadFile("qa_output/memo_encrypted_signed.pdf");
if ($success == 0) {
    print $check->lastErrorText() . "\r\n";
    exit;
}

$empty = chilkat::CkJsonObject->new();
$info = chilkat::CkJsonObject->new();
$success = $check->Protection("getInfo",$empty,$info);
if ($success == 0) {
    print $check->lastErrorText() . "\r\n";
    exit;
}

print "algorithm: " . $info->stringOf("loaded.algorithm") . "\r\n";
print "signatures: " . $check->get_NumSignatures() . "\r\n";
$sigInfo = chilkat::CkJsonObject->new();
$verified = $check->VerifySignature(0,$sigInfo);
print "signature verifies: " . $verified . "\r\n";

#  Signing an encrypted PDF.  This one was opened with only the user password, and its
#  permissions do not allow modifying, so another signature is refused.
$success = $check->SetSigningCert($cert);
if ($success == 0) {
    print $check->lastErrorText() . "\r\n";
    exit;
}

$success = $check->SignPdf($sigOpts,"qa_output/memo_signed_twice.pdf");
if ($success == 0) {
    print "A second signature was refused: the permissions do not allow it." . "\r\n";
}

#  Loaded with the owner password, the same PDF can be signed.  It stays encrypted, and the
#  first signature stays valid because the new one is added as an incremental update.
$owner = chilkat::CkPdf->new();
$owner->put_UserPassword("user-secret");
$owner->put_OwnerPassword("owner-secret");
$success = $owner->LoadFile("qa_output/memo_encrypted_signed.pdf");
if ($success == 0) {
    print $owner->lastErrorText() . "\r\n";
    exit;
}

$success = $owner->SetSigningCert($cert);
if ($success == 0) {
    print $owner->lastErrorText() . "\r\n";
    exit;
}

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

$twice = chilkat::CkPdf->new();
$twice->put_UserPassword("user-secret");
$success = $twice->LoadFile("qa_output/memo_signed_twice.pdf");
if ($success == 0) {
    print $twice->lastErrorText() . "\r\n";
    exit;
}

print "signatures after signing with owner rights: " . $twice->get_NumSignatures() . "\r\n";
$verified = $twice->VerifySignature(0,$sigInfo);
print "first signature still verifies: " . $verified . "\r\n";
$verified = $twice->VerifySignature(1,$sigInfo);
print "second signature verifies: " . $verified . "\r\n";

#  Sample output:

#  algorithm: aes-256
#  signatures: 1
#  signature verifies: True
#  A second signature was refused: the permissions do not allow it.
#  signatures after signing with owner rights: 2
#  first signature still verifies: True
#  second signature verifies: True