PHP Extension

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.

PHP Extension

<?php

include("chilkat.php");

$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 CkBinData();
$success = $jpgBytes->LoadFile('qa_data/jpg/starfish.jpg');
// Make sure your app checks the success/failure of the call to LoadFile..
print 'Original JPG size = ' . $jpgBytes->get_NumBytes() . "\n";

$jwe = new CkJwe();

$jweProtHdr = new CkJsonObject();
$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 CkStringBuilder();
$success = $jwe->EncryptBd($jpgBytes,$sbJwe);
if ($success != true) {
    print $jwe->lastErrorText() . "\n";
    exit;
}

// Show the JWE:
print $sbJwe->getAsString() . "\n";
print 'size of JWE: ' . $sbJwe->get_Length() . "\n";

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

$jwe2 = new CkJwe();
$success = $jwe2->LoadJweSb($sbJwe);
if ($success != true) {
    print $jwe2->lastErrorText() . "\n";
    exit;
}

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

// Decrypt.
$jpgOriginal = new CkBinData();
$success = $jwe2->DecryptBd(0,$jpgOriginal);
if ($success != true) {
    print $jwe2->lastErrorText() . "\n";
    exit;
}

print 'Decrypted JPG size = ' . $jpgOriginal->get_NumBytes() . "\n";

// Save the decrypted JPG to a file.
$success = $jpgOriginal->WriteFile('qa_output/jwe_decrypted_starfish.jpg');

print 'success = ' . $success . "\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

?>