php-simple-jwt/src/Key/JWTDerivedKey.php

<?php

namespace NoccyLabs\SimpleJWT\Key;

class JWTDerivedKey implements KeyInterface
{
    private $key;

    public function __construct(string $password, string $salt, int $iter=100)
    {
        $this->key = hash_pbkdf2("sha256", $password, $salt, $iter, 0, true);
    }

    public function getBinaryKey(): string
    {
        return $this->key;
    }
}