Set JWE Additional Authenticated Data

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetAad, which sets external Additional Authenticated Data (AAD) for a JWE being encrypted, encoding the supplied text with the given charset.

<?php

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

$jwe = new Jwe();

// Protected header: AES key-wrap with AES-256-GCM content encryption.
$header = new JsonObject();
$header->UpdateString('alg', 'A256KW');
$header->UpdateString('enc', 'A256GCM');
try {
    $jwe->SetProtectedHeader($header);

    // The 256-bit key-wrapping key (base64) for recipient index 0.  In production, obtain the key from a
    // secure source rather than hard-coding it.
    $base64Key = 'YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=';
    $jwe->SetWrappingKey(0, $base64Key, 'base64');

    // Set external Additional Authenticated Data (AAD).  The AAD is integrity-protected but not
    // encrypted, and must be supplied again when decrypting.
    $jwe->SetAad('context-info-v1', 'utf-8');

    $sbContent = new StringBuilder();
    $sbContent->Append('This is the secret content.');
    $sbJwe = new StringBuilder();
    $jwe->EncryptSb($sbContent, 'utf-8', $sbJwe);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo $sbJwe->GetAsString(), "\n";