```
"This is the only prop you can use, and the only channel that can exchange matter and information with the real world. So, if you want to prove whether the world you're in is real or fake, you have to focus on this safe."
Chu Anqing suddenly realized and looked up to speak!
"But..." Lin Xian smiled and raised his hand to interrupt her:
"I know what you want to say, definitely to have a friend put something in the safe that I don't know about, then I set a password that nobody else knows. After I go there and open it to confirm the contents, then my friend verifies it, and we can distinguish the truth of that world."
"But don't panic, this problem is far from simple, otherwise, I wouldn't be so troubled, having thought for so long without any viable solution. Because in addition to those previous assumptions, there's an additional restriction—"
