private function setNonce($length = 6){
        $result = '';
        $cLength = strlen(self::NONCE_CHARS);
        for ($i=0; $i < $length; $i++)
        {
           $rnum = rand(0,$cLength - 1);
           $result .= substr(self::NONCE_CHARS,$rnum,1);
        }
        $this->oauthNonce = $result;
  }