暗号

例句：

1. 1. The secret code was broken by a clever thief.
   一个聪明的小偷破解了秘密密码。
2. 2. They used a series of signals to communicate with each other.
   他们使用一系列信号进行相互交流。
3. 3. The cipher is the key to deciphering this message.
   这个密文是解密这条消息的关键。