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

$success = 0;

$jwe = new COM("Chilkat.Jwe");

//  Protected header: AES key-wrap with AES-256-GCM content encryption.
$header = new COM("Chilkat.JsonObject");
$header->UpdateString('alg','A256KW');
$header->UpdateString('enc','A256GCM');
$success = $jwe->SetProtectedHeader($header);
if ($success == 0) {
    print $jwe->LastErrorText . "\n";
    exit;
}

//  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=';
$success = $jwe->SetWrappingKey(0,$base64Key,'base64');
if ($success == 0) {
    print $jwe->LastErrorText . "\n";
    exit;
}

//  Set external Additional Authenticated Data (AAD).  The AAD is integrity-protected but not
//  encrypted, and must be supplied again when decrypting.
$success = $jwe->SetAad('context-info-v1','utf-8');
if ($success == 0) {
    print $jwe->LastErrorText . "\n";
    exit;
}

$sbContent = new COM("Chilkat.StringBuilder");
$sbContent->Append('This is the secret content.');
$sbJwe = new COM("Chilkat.StringBuilder");
$success = $jwe->EncryptSb($sbContent,'utf-8',$sbJwe);
if ($success == 0) {
    print $jwe->LastErrorText . "\n";
    exit;
}

print $sbJwe->getAsString() . "\n";

?>