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Love in Kleptopia needs to be explained better. The problem can only be solved if you can afix two padlocks onto a box, and I was presuming the lock box had a s
by deathanatos 9y ago
Love in Kleptopia needs to be explained better. The problem can only be solved if you can afix two padlocks onto a box, and I was presuming the lock box had a single, normally shaped padlock eye, which would make such a thing impossible.
I find this happens a lot with "thought" problems: I can't solve it (and can often prove that) because the rules of the problem are inadequately explained.
- scrooched_moose 9y agoTo get super pedantic, even if that was the case you could use a lock out tag out type device to still attach two locks. https://www.media-partners.com/upload/i20121017160441/img1.jpg https://www.media-partners.com/upload/i20121017160441/img1.j...
- HanayamaTriplet 9y agoAnother alternative would be to thread a small steel cable with looped ends large enough for two locks through the eye and then lock the loops together.
- keithnz 9y agothe problem is if you introduce new things, then you can solve it like 1. Bolt Cutters 2. Break the box 3. Send the key design via the internet and a link to https://www.youtube.com/watch?v=8M-HYptOMJI https://www.youtube.com/watch?v=8M-HYptOMJI
- oh_sigh 9y agoUnfortunate that they don't show multiple locks in that image.
- matt-attack 9y agoBut they clearly show multiple holes.
- IshKebab 9y agoI haven't looked at the solution but I don't see why it requires a box that can have two padlocks attached. A sends their open padlock and a box to B. B puts their open padlock in the box, and locks it with A's padlock and sends it back. A opens his padlock, puts the ring inside, locks it with B's padlock and sends it back. Maybe it was just too hard for you? :P
- CrazedGeek 9y ago“anything sent through the mail will be stolen unless it is enclosed in a padlocked box” That’s why — A’s open padlock will be stolen.
- millstone 9y agoIn this solution the open padlock would be stolen, because it is not in a locked box.
- ImSkeptical 9y agoIf that's true then shouldn't the double padlocked box be stolen as it is not a padlocked box but is instead a double padlocked box? (Here I'm assuming the "correct" solution is A mails locked box containing ring to B. B adds a lock and returns the box to A. A unlocks lock A and returns the box to B which is locked only with lock B that can be undone by B.)
- BugsJustFindMe 9y ago> A sends their open padlock and a box to B And they are both promptly stolen, because neither is inside a padlocked box. "anything sent through the mail will be stolen unless it is enclosed in a padlocked box". Anything includes padlocks and boxes. In fact, even the padlocked box would be stolen because it's not inside a padlocked box. And if it were, the outer box would just be stolen. The puzzle as written is just turtles all the way down. The proper form of the riddle would be that anything except for a padlocked box will be stolen from the mail.
- ryanx435 9y agoOr just attach a lock that needs a combo (ex: 3,7,15) instead of a key to open it, then tell her the combination after she gets it and the risk of theft is zero. The problem specifically says they are communicating using the internet, so why not? "Hey, I sent you a box. It's locked with a combo lock. Call me when you get it: I want to be talking to you when you see the surprise! I'll tell you the combo on the phone!"
- louisswiss 9y agoCan't believe I didn't think of that before I got to the double padlock solution.
- theoh 9y agoThe situation is actually a bit tricky. If they met over the internet, there's no way to guarantee the absence of a Man-in-the-Middle who has been allowing the romance to proceed without interference, but who tampers with the messages which give the address to which the ring must be sent (and who fakes the message which says the box has been received.) The only way to avoid this possibility (of a man in the middle attack) is to be "introduced" by a third party you already trust. See e.g. https://en.wikipedia.org/wiki/Needham–Schroeder_protocol https://en.wikipedia.org/wiki/Needham–Schroeder_protocol In the absence of a trusted third party, you could be talking to anybody, through any number of lurking intermediaries. If you've got a trusted third party then the problem, as posed, is moot.
- fao_ 9y agoAll of the other solutions are vulnerable to MITM as well, though.
- deleted 9y ago[deleted]
- SilasX 9y agoI initially had considered two padlocks being on the box, but ruled it out because "come on, that would just bring more attention to it such that they'd spend enough to break our measures".
- teraflop 9y agoAlso, the problem assumes that padlocked boxes themselves are not stolen. Presumably we're expected to consider this a reasonable assumption, because a thief wouldn't bother stealing a box that they couldn't open. But just as with public-key cryptography, a thief who can both steal packages and forge return addresses could intercept the box, place their own padlock on it, and then execute the rest of the protocol to perform a classic man-in-the-middle attack.
- Moodles 9y agoReminds me of this: 1, 2, 3, 4, 5, 6, 7, 8, 9,... What comes next? 10 if it's the sequence of natural numbers 13 if it's the sequence of N such that N=2^n for natural numbers n, where N does not contain a 0 153 if it's sequence of N such that the the sum of the digits of N each raised to the power of the number of digits in N equals N.
- mtreis86 9y agoThose problems always bothered me. I think that for any sequence of numbers there is an infinite number of next-in-sequence solutions regardless of the sequence length or numbers contained. One may be more obvious but you can put any number next and find a pattern that matches. Example - what if those are a sequence of digits in pi.
- cabaalis 9y agoI think "What comes next?" is an incomplete question, without any context. "What comes next in the sequence of (blah)?" is a complete question with full context. But that question wouldn't make anybody feel superior. "Identify as many sequences as you can which fit this set of numbers, and tell me the next number in each sequence" is the non-trick actually being asked.
- jameshart 9y agoI think the only sane approach is to apply a Kolmogorov-shaded Occam's Razor, and select, from the set of possible sequences which fit the pattern, the one which has the simplest generating function.
- CamperBob2 9y agoThat can be tricky in itself, though. 1, 2, 3, 4, .... might be a sequence of positive integers, or it might be a subset of pseudo-random digits emitted by a maximal-length shift register sequence. Someone recently pointed out to me that if you were designing hardware to (e.g.) refresh all memory locations in a system, or otherwise visit a set of 2^n sequential locations in no particular order, then using a maximal-length shift register of the appropriate width is actually simpler than a 'simple' adder or subtractor. That could be seen as a literal interpretation of Kolmogorov complexity.
- deleted 9y ago[deleted]
- raverbashing 9y agoYeah, underdetermined/badly explained problems are just irritating. Especially since you don't know what level is the person targeting, or come with a smug answer about some detail that was not specified. I don't waste much time with them to be honest.
- derefr 9y agoAlso, given that 1. these are regular padlocks; 2. Alice and Bob already have a secure communications channel along which information, but not objects, can flow (the Internet); ...then the puzzle has a "cheese" solution: just communicate the metrics of the key along your secure channel, and have your counterparty reproduce the key using them! Padlock keys are essentially number sequences :)