PHP

JWE with Binary Data

See more JSON Web Encryption (JWE) Examples

Demonstrates how to create a JWE that contains a binary payload (such as a JPG image).

Note: This example requires Chilkat v9.5.0.66 or greater.

Chilkat2 PHP

<?php

use Chilkat2\BinData;
use Chilkat2\JsonObject;
use Chilkat2\Jwe;
use Chilkat2\StringBuilder;

$success = false;

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

// Note: This example requires Chilkat v9.5.0.66 or greater.

// Load a JPG file that will be the JWE payload.
$jpgBytes = new BinData();
$jpgBytes->LoadFile('qa_data/jpg/starfish.jpg');
// Make sure your app checks the success/failure of the call to LoadFile..
echo 'Original JPG size = ', $jpgBytes->NumBytes, "\n";

$jwe = new Jwe();

$jweProtHdr = new JsonObject();
$jweProtHdr->AppendString('alg', 'A128KW');
$jweProtHdr->AppendString('enc', 'A128CBC-HS256');
$jwe->SetProtectedHeader($jweProtHdr);

$aesWrappingKey = 'GawgguFyGrWKav7AX4VKUg';
$jwe->SetWrappingKey(0, $aesWrappingKey, 'base64url');

// Encrypt and return the JWE in sbJwe:
$sbJwe = new StringBuilder();
try {
    $jwe->EncryptBd($jpgBytes, $sbJwe);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Show the JWE:
echo $sbJwe->GetAsString(), "\n";
echo 'size of JWE: ', $sbJwe->Length, "\n";

// ---------------------------------------------------------
// Decrypt to get the original JPG file..

$jwe2 = new Jwe();
try {
    $jwe2->LoadJweSb($sbJwe);

    // Set the AES wrap key.
    $jwe2->SetWrappingKey(0, $aesWrappingKey, 'base64url');

    // Decrypt.
    $jpgOriginal = new BinData();
    $jwe2->DecryptBd(0, $jpgOriginal);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo 'Decrypted JPG size = ', $jpgOriginal->NumBytes, "\n";

// Save the decrypted JPG to a file.
try {
    $jpgOriginal->WriteFile('qa_output/jwe_decrypted_starfish.jpg');
    $success = true;
} catch (\Chilkat2\Exception $e) {
    $success = false;
}

echo 'success = ', ($success ? 'true' : 'false'), "\n";

// The output of this program, when tested, was:
// Original JPG size = 6229
// eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0.9YFz_wteV ... 7Et3hKhpxnKEXw
// size of JWE: 8473
// Decrypted JPG size = 6229
// success = True