Hidden codes

例句：

1. 1. The hidden codes in the codebase are a mystery that only the experts can solve.
   代码库中的隐藏代码是一个只有专家才能解开的谜。
2. 2.The team used hidden codes to communicate with each other during the mission.
   团队在任务中使用了隐藏代码来相互沟通。
3. 3. The hidden codes were meant to be unbreakable, but they were eventually cracked by a determined hacker.
   这些隐藏代码原本是坚不可摧的，但最终被一位决心十足的黑客破解。