Hash a Password with Argon2 (Tuned Options)

Demonstrates Crypt2.Argon2HashPassword with explicit options: the cost parameters, saltLen (how many random salt bytes to generate when no salt is given), and an optional secret (pepper).

<?php

use Chilkat2\Crypt2;
use Chilkat2\JsonObject;

$crypt = new Crypt2();

// The password should come from a secure source rather than being hard-coded.
$password = 'correct horse battery staple';

// The Argon2 options are the same members as Argon2DeriveKey, except the salt is optional for
// hashing.  When no "salt" is given, a random salt is generated; "saltLen" (default 16, range 8..1024)
// sets how many random bytes to use.
$json = new JsonObject();
$json->UpdateString('variant', 'argon2id');
$json->UpdateInt('memoryCostKb', 131072);
$json->UpdateInt('iterations', 4);
$json->UpdateInt('parallelism', 2);
$json->UpdateInt('saltLen', 16);

// A secret (pepper) and/or ad may be used, but neither is stored in the returned PHC string.  The
// same values must be supplied to Argon2VerifyPassword for the password to verify.
$json->UpdateString('secret', 'application-wide-pepper');
$json->UpdateString('secretEncoding', 'utf-8');

try {
    $phcHash = $crypt->Argon2HashPassword($password, $json->Emit());
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

echo $phcHash, "\n";