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).

use strict;
use warnings;
use Chilkat2;

my $crypt = Chilkat2::Crypt2->new;

# The password should come from a secure source rather than being hard-coded.
my $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.
my $json = Chilkat2::JsonObject->new;
$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');

my $phcHash = $crypt->Argon2HashPassword($password, $json->Emit());
if (!$crypt->LastMethodSuccess) {
    print $crypt->LastErrorText, "\n";
    exit;
}

print $phcHash, "\n";