Set a Per-Recipient JWE Header

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetRecipientHeader, which sets the per-recipient unprotected header for a recipient index.

<?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 the per-recipient unprotected header for recipient 0, for example a key id used to identify
    // which key a recipient should use.
    $recipHeader = new JsonObject();
    $recipHeader->UpdateString('kid', 'recipient-key-1');
    $jwe->SetRecipientHeader(0, $recipHeader);

    $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";