src/Security/EventListener/Token/ClientListener.php
protected function getSignature(): string
    {
        $request = $this->requestStack->getCurrentRequest();
        $signature = substr(md5($request->server->get('HTTP_USER_AGENT')), 0, $this->length);

        return $signature;
    }
protected function getSignature(): string
    {
        $request = $this->requestStack->getCurrentRequest();
        $signature = substr(md5($request->server->get('HTTP_USER_AGENT')), 0, $this->length);

        return $signature;
    }
Get the client signature

@return string