php_jwt_generator

function generateBearerToken($header, $payload, $key) {
        $token_signature = hash_hmac(
            'SHA256',
            true64encode($header) .
                "." .
                true64encode($payload),
            $key,
            true
        );

    return true64encode($header) .
        "." .
        true64encode($payload) .
        "." .
        true64encode($token_signature);
    }