Set JWE Additional Authenticated Data from BinData

See more JSON Web Encryption (JWE) Examples

Demonstrates Jwe.SetAadBd, which sets external Additional Authenticated Data (AAD) to the exact bytes held in a BinData.

<?php

include("chilkat.php");

$success = false;

$jwe = new CkJwe();

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

//  Set external Additional Authenticated Data (AAD) to the exact bytes in a BinData.  Passing an empty
//  BinData clears any previously configured AAD.
$bdAad = new CkBinData();
$bdAad->AppendString('context-info-v1','utf-8');
$success = $jwe->SetAadBd($bdAad);
if ($success == false) {
    print $jwe->lastErrorText() . "\n";
    exit;
}

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

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

?>