45
4
How well do you know the site? Let's find out.
This is a cops-and-robbers challenge. Robber's thread.
As a cop, you need to:
- Find a non-deleted, non-closed challenge on this site to answer. The challenge cannot have the following tags: cops-and-robbers, popularity-contest, code-trolling, underhanded, busy-beaver, king-of-the-hill, tips, answer-chaining. The challenge must have restrictions on valid output.
- Write a valid submission for the challenge, in a free language found on Wikipedia or esolangs.org or tryitonline. The submission does not have to be competitive, only valid. EDIT: Hashing in your submission is not allowed
- Post the submission here, keeping the challenge secret. You must post the entire submission, as well as the language (and version, if applicable).
After a week, if nobody has found the challenge you are answering, you may post the challenge that your submission is answering, at which point, your submission is safe. It is worth N points, where N is the number of upvotes on the challenge (as of 2016-11-17) (Higher is better)
To crack your challenge, a robbers need to find any challenge that the submission is a valid submission for.
Notes:
- If a challenge requires an output of
X
, and you outputXY
orYX
whereY
is anything besides whitespace, the submission is not valid for that challenge. - A challenge newer than 2016-11-17 is not allowed.
- Languages newer than the hidden challenge are allowed.
- I reserve the right to ban certain challenges if they are widely applicable (could be applied to the majority of all submissions).
- Thanks to Daniel for the initial idea!
Uncracked Submissions:
<script>site = 'meta.codegolf'; postID = 5686; isAnswer = false; QUESTION_ID = 100357;</script><script src='https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js'></script><script>jQuery(function(){var u='https://api.stackexchange.com/2.2/';if(isAnswer)u+='answers/'+postID+'?order=asc&sort=creation&site='+site+'&filter=!GeEyUcJFJeRCD';else u+='questions/'+postID+'?order=asc&sort=creation&site='+site+'&filter=!GeEyUcJFJO6t)';jQuery.get(u,function(b){function d(s){return jQuery('<textarea>').html(s).text()};function r(l){return new RegExp('<pre class="snippet-code-'+l+'\\b[^>]*><code>([\\s\\S]*?)</code></pre>')};b=b.items[0].body;var j=r('js').exec(b),c=r('css').exec(b),h=r('html').exec(b);if(c!==null)jQuery('head').append(jQuery('<style>').text(d(c[1])));if (h!==null)jQuery('body').append(d(h[1]));if(j!==null)jQuery('body').append(jQuery('<script>').text(d(j[1])))})})</script>
Are cops required to provide any information about the nature of the code's expected input? (e.g. a lot of input might be invalid and cause the code to crash) – Gabriel Benamy – 2016-11-18T19:15:27.700
No, the cops only need to provide the code + language. – Nathan Merrill – 2016-11-18T19:16:47.303
2Related meta post – Loovjo – 2016-11-18T19:21:12.420
What are the rules about languages which are newer than the challenge? Are they disallowed due to being newer than this challenge, or newer than the hidden challenge? – None – 2016-11-18T19:24:12.913
Languages newer than the hidden challenge are allowed. – Nathan Merrill – 2016-11-18T19:26:03.903
Any limit as to how many submissions per user, or per user and language? – Luis Mendo – 2016-11-18T19:42:34.053
Is the byte count we report in this challenge the total number of bytes, or based on the scoring of the challenge we're posting for (i.e. if the challenge offered a % count reduction, would we apply that for our answers here?) – Yodle – 2016-11-18T19:46:22.450
1Byte counts are not required. – Nathan Merrill – 2016-11-18T19:47:52.710
nathan may make it so that any challenge which the program provides valid IOs for is an acceptable crack? – tuskiomi – 2016-11-18T20:30:14.743
@tuskiomi if I understand you, any challenge that the program provides valid input/output for is a valid crack. – Nathan Merrill – 2016-11-18T20:32:01.593
Within an hour on which computer? – Mego – 2016-11-18T23:39:55.563
1There are many challenges where solutions will take much longer than an hour to compute for valid inputs. The time limit is not a good idea. – Mego – 2016-11-18T23:51:11.667
Rather than trying to indirectly prevent the impossible hash answers with the time limit, i think you should just directly ban hashing... – FlipTack – 2016-11-18T23:53:37.570
I disagree. There are lots of other ways to get around hashing (unscramble and eval). I prefer the time limit. If the challenge can't be solved in under an hour, then that's an unfortunate side effect – Nathan Merrill – 2016-11-18T23:57:15.427
2@NathanMerrill The current phrasing suggests that if there exists an input that will take an hour to compute the result for, the answer is not valid. This means basically every non-trivial challenge. – a spaghetto – 2016-11-19T00:00:01.387
1Obligatory link to the Things to Avoid post. – Mego – 2016-11-19T00:13:10.723
1I don't understand the urgency to ban cryptographic hashes since they are unlikely to be useful to cops. – feersum – 2016-11-19T04:25:32.350
Counterexample: generate every possible program until you generate one that matches a hash. Run it. – Nathan Merrill – 2016-11-19T04:27:26.923
4@NathanMerrill Not feersum here, but as I've commented on Mego's submission, there's no guarantee you won't hit another hash collision before the intended one. I believe cops should have to be certain that their program is indeed the first one that matches, in which case if the cop can verify it then robbers can too. – Sp3000 – 2016-11-19T04:31:36.347
@NathanMerrill That does NOT work. Collision avoidance of cryptographic hashes is based on probability, not magic. – feersum – 2016-11-19T04:32:50.470
@feersum why not? – Nathan Merrill – 2016-11-19T04:33:41.993
Sp already explained it. – feersum – 2016-11-19T04:35:12.340
1Having said that, other forms of cryptography might be problematic, e.g. semiprime factorisation which is a problem most CnRs have (just a side note). – Sp3000 – 2016-11-19T04:45:51.447
We need a PPCG-introspection tag :-) – Luis Mendo – 2016-11-19T11:22:14.620
I'm a bit unsure about the rules regarding single value outputs... Would a challenge asking for the number of letters in a string be disallowed, since the output is a single number? What about finding the n'th prime? What about challenges asking for
true/false
? – Stewie Griffin – 2016-11-19T23:48:39.513The key here is that they allow any numerical output for any input (aka, it doesn't matter what number you print, it's valid) – Nathan Merrill – 2016-11-19T23:51:09.990
That said, it was simply a reiteration of the clearer requirement: The challenge must have restrictions on valid output. I removed it in interest of clarity – Nathan Merrill – 2016-11-19T23:54:14.977
1Total score 348. What was the winning criteria? – Blue – 2016-11-26T18:59:14.113