How to establish secure communication over insecure channel. Merkle's puzzles.
[[[name:smuggler section:78
It's a puppet show. There are two hills on the stage with country border between them. Law-abiding citizen is on the right hill. Smuggler enters the stage on the left.
SMUGGLER: Hey, you!
CITIZEN: Who? Me?
SMUGGLER: Do you like booze?
CITIZEN: Sure I do. And who are you?
SMUGGLER: I'm the person who will sell you some booze.
CITIZEN: What about cigarettes?
SMUGGLERS: Sure thing. Cheap Ukrainian variety for $1 a pack. Also Slovenian Mariboro brand.
CITIZEN: Thanks God! I am getting sick of our government trying to make me healthy!
Border patrol emerges from a bush in the middle of the stage.
PATROL: Forget about it, guys! This is a state border. Nothing's gonna pass one way or the other. You better pack your stuff and go home.
SMUGGLER: Ignore him. We'll meet later on at some other place, without border patrol around, and you'll get all the booze and cigarettes you want.
PATROL: Ha! I would like to see that. Both of you are going to end up in jail.
CITIZEN: He's right. If you tell me where to meet, he's going to hear that, go there and arrest us.
...
Smuggler has a list of possible places to meet:
- Big oak at 57th mile of the border.
- Lower end of Abe Smith's pasture.
- ...
- ...
He obfuscates each entry and shout them to the citizen in no particular order.
Citizen chooses one of the puzzles and de-obfuscates it. It takes him 10 minutes. The de-obfuscates message reads: "18. Behind the old brick factory."
CITIZEN (cries): Eighteen!
SMUGGLER: Ok, got it, let's meet there in an hour!
PATROL: Oh my, oh my. I am much better at de-obfuscation than that moron citizen. I've already got two messages solved. But one has number 56, the other number 110. I have no idea which one is going to be number 18. There's no way I can find the right one in just one hour!
The curtain comes down. Happy gulping sounds can be heard from the backstage.
]]]