(PHP Extension) JWE using "dir" Direct use of Shared Symmetric Key

Demonstrates how to create a JWE using the "dir" alg -- which is to directly use a shared symmetric key.

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

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<?php

// The version number (9_5_0) should match version of the Chilkat extension used, omitting the micro-version number.
// For example, if using Chilkat v9.5.0.48, then include as shown here:
include("chilkat_9_5_0.php");

// 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.

$plaintext = 'Live long and prosper.';

$jwe = new CkJwe();

// First build the JWE Protected Header..
$jweProtHdr = new CkJsonObject();
$jweProtHdr->AppendString('alg','dir');
$jweProtHdr->AppendString('enc','A128GCM');

// Don't forget to actually provide the protected header to the JWE object:
$jwe->SetProtectedHeader($jweProtHdr);

// The JWE is to use 128-bit AES GCM encryption as specified by the "enc" parameter.
// Given that the "alg" = "dir", we are to directly specify the AES GCM key.
// (It is assumed that the decrypting side also has knowledge of the direct key to be used..)

// Our key will be these 16 hex bytes: 000102030405060708090A0B0C0D0E0F

// The SetWrappingKey method is also used for "dir" direct keys.
// However, if there are multiple recipients, they must all share the same CEK (Content Encryption Key),
// which is specified by calling SetWrappingKey with an index of 0.

$recipientIndex = 0;
$jwe->SetWrappingKey($recipientIndex,'000102030405060708090A0B0C0D0E0F','hex');

// Encrypt and return the JWE:
$strJwe = $jwe->encrypt($plaintext,'utf-8');
if ($jwe->get_LastMethodSuccess() != true) {
    print $jwe->lastErrorText() . "\n";
    exit;
}

// Show the JWE we just created:
print $strJwe . "\n";

// Decrypt the JWE.
$jwe2 = new CkJwe();
$success = $jwe2->LoadJwe($strJwe);
if ($success != true) {
    print $jwe2->lastErrorText() . "\n";
    exit;
}

$jwe2->SetWrappingKey(0,'000102030405060708090A0B0C0D0E0F','hex');

// Decrypt.
$originalPlaintext = $jwe2->decrypt(0,'utf-8');
if ($jwe2->get_LastMethodSuccess() != true) {
    print $jwe2->lastErrorText() . "\n";
    exit;
}

print 'original text: ' . "\n";
print $originalPlaintext . "\n";

// Sample output:
// eyJhbGciOiJkaXIiLCJlbmMiOiJBMTI4R0NNIn0..20HX5Huc7f1nQC4pBUtiCQ.axFZIxtZy5j0ifJQUzGXLKIpsBuxJA.eBrOC-NrsreN6JeGuOPk1g
// original text: 
// Live long and prosper.

?>