public function sendGetCipherKeysFromUser($numbers, $replaceKey = false)
    {
        if (!is_array($numbers)) {
            $numbers = [$numbers];
        }

        $this->replaceKey = $replaceKey;
        $msgId = $this->nodeId['cipherKeys'] = $this->createIqId();

        $userNode = [];
        foreach ($numbers as $number) {
            $userNode[] = new ProtocolNode('user',
              [
                  'jid' => $this->getJID($number),
              ], null, null);
        }
        $keyNode = new ProtocolNode('key', null, $userNode, null);
        $node = new ProtocolNode('iq',
            [
                'id'    => $msgId,
                'xmlns' => 'encrypt',
                'type'  => 'get',
                'to'    => Constants::WHATSAPP_SERVER,
            ], [$keyNode], null);

        $this->sendNode($node);
        $this->waitForServer($msgId);
    }