PHP 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. Chilkat2 PHP

<?php

use Chilkat2\JsonObject;
use Chilkat2\Pdf;

// 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 JsonObject();
$jsonOut = new JsonObject();
$info = new JsonObject();

// AES-256, the default.  Saved as PDF 1.7 with Adobe extension level 8.
$pdf1 = new Pdf();
try {
    $pdf1->LoadFile('qa_data/pdf/two_page_memo.pdf');

    $pdf1->UserPassword = 'user-secret';
    $pdf1->OwnerPassword = 'owner-secret';
    $json->UpdateString('algorithmChoice', 'aes-256');
    $pdf1->Protection('encrypt', $json, $jsonOut);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'aes-256 will be saved as PDF ', $jsonOut->StringOf('pending.pdfVersion'), ', Adobe extension level ', $jsonOut->IntOf('pending.adobeExtensionLevel'), "\n";
try {
    $pdf1->WriteFile('qa_output/memo_aes256.pdf');

    $pdf1->PreLoadCheck('qa_output/memo_aes256.pdf', $info);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo '  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 Pdf();
try {
    $pdf2->LoadFile('qa_data/pdf/two_page_memo.pdf');

    $pdf2->UserPassword = 'user-secret';
    $pdf2->OwnerPassword = 'owner-secret';
    $json->UpdateString('algorithmChoice', 'aes-128');
    $pdf2->Protection('encrypt', $json, $jsonOut);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'aes-128 will be saved as PDF ', $jsonOut->StringOf('pending.pdfVersion'), "\n";
try {
    $pdf2->WriteFile('qa_output/memo_aes128.pdf');

    $pdf2->PreLoadCheck('qa_output/memo_aes128.pdf', $info);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo '  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 Pdf();
try {
    $pdf3->LoadFile('qa_data/pdf/two_page_memo.pdf');

    $pdf3->UserPassword = 'user-secret';
    $pdf3->OwnerPassword = 'owner-secret';
    $json->UpdateString('algorithmChoice', 'rc4-128');
    $pdf3->Protection('encrypt', $json, $jsonOut);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'rc4-128 will be saved as PDF ', $jsonOut->StringOf('pending.pdfVersion'), "\n";
try {
    $pdf3->WriteFile('qa_output/memo_rc4_128.pdf');

    $pdf3->PreLoadCheck('qa_output/memo_rc4_128.pdf', $info);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo '  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