PHP Extension Requires Chilkat v11.7.0+

Choose the PDF Encryption Algorithm: AES-256, AES-128 or RC4

See more PDF Protection Examples

Demonstrates the algorithmChoice option of the encrypt operation. aes-256 is the default and the one to use unless an older reader must open the file. aes-128 is for readers that predate AES-256. rc4-128 and rc4-40 are broken ciphers kept only for very old readers. Each algorithm needs a minimum PDF version, and the file header is raised to it when the PDF is saved, never lowered. A PDF saved with RC4 is written with a classic cross-reference table so that those old readers can parse it. 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.

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

$json = new CkJsonObject();
$jsonOut = new CkJsonObject();
$info = new CkJsonObject();

//  AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
$pdf1 = new CkPdf();
$success = $pdf1->LoadFile('qa_data/pdf/two_page_memo.pdf');
if ($success == false) {
    print $pdf1->lastErrorText() . "\n";
    exit;
}

$pdf1->put_UserPassword('user-secret');
$pdf1->put_OwnerPassword('owner-secret');
$json->UpdateString('algorithmChoice','aes-256');
$success = $pdf1->Protection('encrypt',$json,$jsonOut);
if ($success == false) {
    print $pdf1->lastErrorText() . "\n";
    exit;
}

print 'aes-256 will be saved as PDF ' . $jsonOut->stringOf('pending.pdfVersion') . ', Adobe extension level ' . $jsonOut->IntOf('pending.adobeExtensionLevel') . "\n";
$success = $pdf1->WriteFile('qa_output/memo_aes256.pdf');
if ($success == false) {
    print $pdf1->lastErrorText() . "\n";
    exit;
}

$success = $pdf1->PreLoadCheck('qa_output/memo_aes256.pdf',$info);
if ($success == false) {
    print $pdf1->lastErrorText() . "\n";
    exit;
}

print '  saved file: ' . $info->stringOf('algorithm') . ', PDF ' . $info->stringOf('pdfVersion') . "\n";

//  AES-128, for readers that predate AES-256.  Saved as PDF 1.6.
$pdf2 = new CkPdf();
$success = $pdf2->LoadFile('qa_data/pdf/two_page_memo.pdf');
if ($success == false) {
    print $pdf2->lastErrorText() . "\n";
    exit;
}

$pdf2->put_UserPassword('user-secret');
$pdf2->put_OwnerPassword('owner-secret');
$json->UpdateString('algorithmChoice','aes-128');
$success = $pdf2->Protection('encrypt',$json,$jsonOut);
if ($success == false) {
    print $pdf2->lastErrorText() . "\n";
    exit;
}

print 'aes-128 will be saved as PDF ' . $jsonOut->stringOf('pending.pdfVersion') . "\n";
$success = $pdf2->WriteFile('qa_output/memo_aes128.pdf');
if ($success == false) {
    print $pdf2->lastErrorText() . "\n";
    exit;
}

$success = $pdf2->PreLoadCheck('qa_output/memo_aes128.pdf',$info);
if ($success == false) {
    print $pdf2->lastErrorText() . "\n";
    exit;
}

print '  saved file: ' . $info->stringOf('algorithm') . ', PDF ' . $info->stringOf('pdfVersion') . "\n";

//  RC4-128, a broken cipher, only for readers too old for AES.  Saved as PDF 1.4.
$pdf3 = new CkPdf();
$success = $pdf3->LoadFile('qa_data/pdf/two_page_memo.pdf');
if ($success == false) {
    print $pdf3->lastErrorText() . "\n";
    exit;
}

$pdf3->put_UserPassword('user-secret');
$pdf3->put_OwnerPassword('owner-secret');
$json->UpdateString('algorithmChoice','rc4-128');
$success = $pdf3->Protection('encrypt',$json,$jsonOut);
if ($success == false) {
    print $pdf3->lastErrorText() . "\n";
    exit;
}

print 'rc4-128 will be saved as PDF ' . $jsonOut->stringOf('pending.pdfVersion') . "\n";
$success = $pdf3->WriteFile('qa_output/memo_rc4_128.pdf');
if ($success == false) {
    print $pdf3->lastErrorText() . "\n";
    exit;
}

$success = $pdf3->PreLoadCheck('qa_output/memo_rc4_128.pdf',$info);
if ($success == false) {
    print $pdf3->lastErrorText() . "\n";
    exit;
}

print '  saved file: ' . $info->stringOf('algorithm') . ', PDF ' . $info->stringOf('pdfVersion') . "\n";

//  Sample output:

//  aes-256 will be saved as PDF 1.7, Adobe extension level 8
//    saved file: aes-256, PDF 1.7
//  aes-128 will be saved as PDF 1.6
//    saved file: aes-128, PDF 1.6
//  rc4-128 will be saved as PDF 1.4
//    saved file: rc4-128, PDF 1.4

?>