text:
Unscramble the Source Code

Note: This challenge is now closed to new cop submissions. This is to ensure that no one can post submissions that only remain uncracked because there aren't enough robbers interested in the challenge anymore.

In this game of cops-and-robbers, each cop will write a simple program to give a single output.  They will then make public four things about their program:

The language
The program length
The desired output
A scrambled-up version of the source code

Then, the robbers must unscramble the source code so that their program functions like the original.

Cop Rules
You are to write a simple program, which the robbers will try to recreate.
Your original program must have a simple functionality: upon execution, it outputs a single string/number and halts.  It should give the same output regardless of when/where it is run, and should not depend on extra libraries or the internet.
Your program and output must use printable ASCII (newlines and spaces allowed). The output should be no more than 100 characters long, and the program should take less than about 5 seconds to run on a reasonable machine. You are also not allowed to use hashing (or other cryptographic functions) in your program
Then, you provide a scrambled-up version of the source code and the required output.  You can scramble up your source code however you may like, as long as characters are conserved.
Your score is the shortest program you have submitted which hasn't been cracked.  After a period of one week, an uncracked submission will become immune.  In order to claim this immunity, you should edit your answer to show the correct answer. (Clarification: Until you reveal the answer, you are not immune and can still be cracked.) The lowest score wins.
Simple Example Cop Answers

Perl, 20
ellir"lnto Wo d";prH
Hello World

Or...

Perl, 15
*3i)xp3rn3*x3t(
272727

Robber Rules
Robbers will post their cracking attempts as answers in a separate thread, located here.
You have one attempt at cracking each submission.  Your cracking attempt will be an unscrambled version of the source code.  If your guess matches the description (same characters, output, and of course language), and you are the first correct guess, then you win a point.  It is important to note that your program does not have to exactly match the original, simply use the same characters and have the same functionality.  This means there could be more than one correct answer.
The robber with the most points (successful cracks) wins.
Simple Example Robber Answers

Your program was print "Hello World";.  (Although print"Hello World" ; could have also worked.)
Your program was print(3**3x3)x3

Safe Submissions

ASP/ASP.Net, 14 (Jamie Barker)
Befunge-98, 15 (FireFly)
GolfScript, 16 (Peter Taylor)
CJam, 19 (DLosc)
GolfScript, 20 (user23013)
Perl, 21 (primo)
Python, 23 (mbomb007)
Ruby, 27 (histocrat)
SAS, 28 (ConMan)
Ruby, 29 (histocrat)
Python, 30 (mbomb007)
JavaScript, 31 (hsl)
Ruby, 33 (histocrat)
Marbelous, 37 (es1024)
Ruby, 43 (histocrat)
PHP, 44 (kenorb)
Ruby, 45 (histocrat)
Marbelous, 45 (es1024)
Python 2, 45 (Emil)
PHP, 46 (Ismael Miguel)
Haskell, 48 (nooodl)
Python, 51 (DLosc)
Python, 60 (Sp3000)
Python 2, 62 (muddyfish)
JavaScript, 68 (Jamie Barker)
Mathematica, 73 (Arcinde)
Haskell, 77 (proudhaskeller)
Python, 90 (DLosc)
C++, 104 (user23013)
ECMAScript 6, 116 (Mateon1)
C++11, 121 (es1024)
Grass, 134 (user23013)
PowerShell, 182 (christopherw)

Unsolved Submissions
In order of time of posting.  This list courtesy of many users.

CoffeeScript, 96 (soktinpk)
Python 3, 70 (Sp3000)
TinyMUSH 3.1, 20 (Muqo)
GolfScript, 32 (Beta Decay)
Python 2, 101 (Mateon1)
Lua, 49 (ChipperNickel)
Python, 61 (imallett)
Java 6+, 218 (nhahtdh)
CJam, 51 (Martin Büttner)
J, 22 (FireFly)
Marbelous, 106 (es1024)
Marbelous, 107 (es1024)
JavaScript, 79 (FireFly)
CJam, 47 (user23013)
Rust, 118 + Clojure, 106 + others (Vi.) - version 2
Marbelous, 144 (es1024)
Python 2, 80 (MrWonderful)
Perl, 53 (DLosc)
Perl, 26 (primo)
Mathematica, 31 (Arcinde)
Marbelous, 144 (es1024)
Assembly, 78 (krzygorz)
J, 14 (algorithmshark)
Java 8, 157 (TheBestOne)

A small tool to verify solutions, courtesy of n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳

$(function(){function e(){var e=$("#ignore-space").is(":checked");var t=$("#source").val().split("").sort();var n=$("#editor").val().split("").sort();var r,i=0;for(r=0;r<t.length;){if(t[r]==n[i]){t.splice(r,1);n.splice(i,1)}else if(t[r]>n[i]){i++}else{r++}}$("#display").val(t.join(""));n=n.join("");if(e){n=n.replace(/[\r\n\t ]/g,"")}if(n.length!=0){$("#status").addClass("bad").removeClass("good").text("Exceeded quota: "+n)}else{$("#status").addClass("good").removeClass("bad").text("OK")}}$("#source, #editor").on("keyup",function(){e()});$("#ignore-space").on("click",function(){e()});e()})
textarea{width:100%;border:thin solid emboss}#status{width:auto;border:thin solid;padding:.5em;margin:.5em 0}.bad{background-color:#FFF0F0;color:#E00}.good{background-color:#F0FFF0;color:#2C2}

Scrambled Source

<textarea id="source" class="content" rows="10"></textarea>

Unused Characters

<textarea id="display" class="content" rows="10" readonly></textarea>

Your Solution

<input type="checkbox" id="ignore-space" name="ignore-space"/>
Ignore space characters

OK

<textarea id="editor" class="content" rows="10"></textarea>

Scramble means permute the characters?

@xnor Yes, that's what it means.

You might want to forbid hashing... http://codegolf.stackexchange.com/questions/40304/code-crosswords#comment92987_40304

It might be an idea to maintain a list of uncracked submissions in the question, for when things get messy.

Does printable ASCII mean newlines are forbidden?

@Dennis No, that wasn't my intent.

Can cops submit multiple programs? Also, are languages which may not be available to everyone (Mathematica) allowed?

@FoxWilson I'll say yes to both of those.  When a cop submits multiple programs, his score is the shortest uncracked one.

You should probably specify that the winner must post the original source code after one week.  What prevents me from posting gibberish and claiming that none of the robbers got the right answer?

I thought "Oh, il just write a malbolge program, scramble it, and win this thing!". But then, i tried to write a malbolge program.

@user2023861 I decided that would be a good rule.

@PhiNotPi I took the liberty of adding a list of unsolved submissions to the question; hope you don't mind.

@Rodolvertice How about a Brainfuck program?

Why should solutions by the authors be posted in the robbers thread as well? Why not just edit their answer here with the solution?

Can you use an error or function output as your code output? E.g. php -r "blah" would generate the output: Parse error: syntax error...?

Added code golf, because the scoring is still "shortest wins".

How about decompress functions (e.g. gunzip)?

@MartinBüttner I was intending to keep all the solutions in the same thread, but it doesn't really matter to me.  I changed it to "edit your answers" since that's what people seem to want.

I had fun with this (PHP) then realized it doesn't qualify since the output changes based on when you run it (displays current time) _meet_Lost_leAch (need(feed)strong)lizards''meat''crate/Aeiou;

Please no one post anything in NP hard languages like Brainfuck - we would be doooooomed...

Warning: Cops, do not use Ideone to test your submissions, as it stores your programs and other people can see them.

@Rodolvertice Can't you set the privacy setting?

@Sp3000 Had no idea that existed haha... Well it seems you need an account for true privacy (besides the link sharing secrecy option)

How is "hashing" defined?

srand should probably count as a cryptographic function.

I love this site.

Greetings OP. Is it possible for me to start a bounty of 200 points on my answer? Here is the link: http://codegolf.stackexchange.com/a/41295/14732

@IsmaelMiguel You can do it in the robbers' thread, but you can wait until someone cracks it.

@user23013 Thank you for the edits, but you deleted the wrong link. You deleted this: http://codegolf.stackexchange.com/a/41295/14732 which is still uncracked, but you let this: http://codegolf.stackexchange.com/a/41340/14732 which was the cracked answer.

Fixed. But it was deleted by @es1024.

I think activity is slowing down...

Would it be possible to post new cop submissions with an extended time limit for the robbers (for example, 1-2 months?) This could fix the problem of cops only winning because time ran out before any interested robbers cracked it.

Python 3, size 74 (Cracked)
Python just wasn't the same after being re-educated by Big Brother.
Input:
print(war is peace)
print(freedom is slavery)
print(ignorance is strength)

There are two newlines at the end of lines 1 and 2.
Output:
True
True
True

Note that each True is in its own line.

What's behind door 101?

I originally had 2+2==5 as a fourth statement until I found that the = made it too easy.

Nice 1984 reference.

Cracked. That was excellent.

Python 3, size 12 (Cracked)
print (abcd)

My program produces no output and no errors.

Cracked. Nice, the solution is very counter-intuitive.

Very nice, I was going for int for a while.

@matsjoyce Nicely done. That was my intended solution.

@matsjoyce Yes, I expected someone would do this eventually. Still, I encourage everyone to not spoil themselves and try to solve it by hand. I assure you it's a cute solution.

I think I got it. The solution I found does not work if I first type python and then type my solution at the prompt. But it does work, if I put my solution in a file and type python file.

@kasperd That's right, it works only if run from a file. Looks like you have it.

CJam, size 20 (Cracked)
Code
"Stop, Hammer time!"

Output
2.956177636986737

Cracked.

Wait, are you sure you want force others to stop answering this question, in order to close this challenge single-handedly!? -1 (the code contains Hammer)

Python 2, size 50
Cracked
We already know the Answer to the Question, but what's the Question?
Code
print *********************--///222222222222222222

Note that there are no trailing spaces or newlines. The only whitespace character is the single space after print.
Output
42

I've attempted to balance code length and difficulty, but it wouldn't surprise me if I missed it a bit either way. Hopefully it's enough to discourage brute force, at least.

Cracked

This would have been better with size 42.

Pyth - 71 Cracked
Code
C-3P0: "Sir, the possibility,..."*
Han Solo: "Never Tell Me The Odds!"

Output
3720

*Originally, George Lucas had Han interrupt C3-PO.**
**He called this his greatest idea since Jar-Jar.

Interesting note: despite all the changes that Pyth has gone through, there is still a valid answer here!

Original

 ts,*s,y30 l" : : i i Han Solo "eP-C"h"TsrhT

Explanation

 The remaining characters go on the next line. Pyth only interprets the first line of a file.ts, make a 2-tuple and get their sum -1.* multiply:s,y30 l"..." sum the 2-tuple containing 2*30 and the length of the string (18).eP-C"h"T get the largest prime factor of h's ascii value minus 10 (47).srhT get the sum of numbers from 0-10.All in all, this basically just computes: (30*2+18)*(47)+55-1. After reading @isaacg's answer I noticed there is an extremely simple solution: *h30tC"y" which is 31*120.

Updated

 *h30tC"y" "-P:Sir, e possibilit,...Han Solo: Never Tell Me The Odds!"Still works even after all this time...

Sorry for poor explanation formatting, I don't know how to use spoiler blocks :S (@Sp3000 made it a bit nicer for you, though)
Now you can run Pyth online! Try it here. Thanks @isaacg :)

The above may contain blatantly made-up information about the creation of Star-Wars.

cracked

@FryAmTheEggman You can use tags in blocks, e.g.

CJam, size 51 [SAFE]
Code
main(int argc,char* argv){printf("Hello, World!");}

Output
55
2292213229222231957511222223333751125537511222222135723331131931959319319

You can play around with it in the online interpreter.
This should be more crackable than it looks.
Hint

 Start with the second line of the output. A few digits don't appear in it all, and others suspiciously often. Why could that be? If you can decipher that, the rest should almost fall in place.

Solution

 "that rrrrraging london Hail!v"{elccimf(;W))},(*,pa

 The weather must have been pretty bad when I came up with that anagram...

 The hint was supposed to point towards the fact that the second line is made up of squashed-together prime factorisations. I was hoping that from there it would be possible to determine how many and which characters go into the string, leaving only a few characters at the end.

Wait is this scrambled???

Befunge-98, size 15 [SAFE]
Code
"quick"
*+.@\_j

Output
3314

Original

"u_ji@q.+k*c
"
 A curious but somewhat well-known feature of Befunge is that you can terminate a string with the same quote that begins it, which in essence pushes that entire line (except the quote) on the stack.  As an extra trick, I re-use the same string again, by making use of u to reverse the instruction pointer.  Then it's just some arithmetic: the core idea is to sum up all those values (which is done using k to repeat the + operation).

Which interpreter(s) have you tested it on, and in particular what assumptions do they make about cell bitwidth?

@PeterTaylor I've tested it on cfunge under x86_64 linux.  Some testing seems to indicate it uses signed 64-bit integers, although I can say that my solution doesn't depend on overflow semantics so I'm not sure if it matters.

Ok, so I shouldn't be looking for 8-bit overflows. Shame, that might have simplified it ;)

Ugh. I made programs to print 3312, 3300, and several others near 3314. So close...

@Quincunx excellent... :P

Ruby, 17 (Cracked)
Going for something really short this time.
inprt N=2,*'~~~%'

Output:
2
2

Cracked. (With some help from Sp3000)

GolfScript (16 bytes) [SAFE]
%%()*../1129n{}~

Expected output:
-117345085515973157874551915956356303213327583847247840186528288852476459638212404362749

Original source:

 n)~{.*911%(}./2%

Is this expected output excluding the trailing newline, or will the newline simply not be outputted?

@ProgramFOX, the output will end in a newline. The only ways I know of avoiding that would require :.

Python, 69 chars [cracked by grc]
Scrambled:
((((((((((((())))))))))))),,,,accdddiiiiillmmnopprrrrrssssssttttttttu

Output:
1083

This one's just a harmless bit of fun :) Tested on CPython 2.7.8, 3.3.2 and for the heck of it PyPy3 2.3.1.

Explanation

 Uses built-in functions str, dict, list to build up a string and then applies map with ord to convert the string to a list of ints, which are then summed.

Cracked.

Python, size 56 (cracked)
Code
for i in "iprint()".join(([2,3,7,0,9,chr((-7+732^70)])))
Output
hi mom

Python 2? or 3?

@Geobits, either one works.

Cracked.

Python 3, 70 chars
Scrambled:
""(((())))****++++222222222;;;;;=======cccccccccceeeiinnpprrttxxxxxxxx

Output (99 chars long):
388626024960000000000026872002432000000000000676169243200000000000007317718780000000000000028820330

Update
It's been a week, so rather than posting the answer, here's a hint:

 Try taking the square root of the number and working from there

Pyth, 11
\\,,"$: Ndw

Output:
",input(),"

Cracked.

JavaScript, 94 Cracked by FireFly
alert(' '' '''((()))+++,,,,,,,,,,,,,000111111114444577888;;;;;======[[[]]]aaafhinorrrrvvvxx||)

Output
fun in the sun

Original

a=alert;v='';r=[1,7,8,14,11,8,14,10,0,5,14,4,7,8];for(x in r)v+=('h'+(1==0)+a)[r[x]]||'';a(v);

I have a feeling, this won't work in all browsers/engines. What environment did you test this in?

Cracked.

Oh... and I was convinced you had alert first, since the indices matched up so well with the needed characters. Interesting coincidence.

I actually had it first too when I started working on it, but I changed it to reduce browser differences.

Doesn't work on Chrome. I have the latest version. It says Syntax Error: Unexpected String

Ruby, 38 - cracked by Martin Büttner
print(succ(downcase!))$$$..[[]]6e0<><_

Output:
u

Original:

 $6.pincdwnca[]rescue$><<$!.to_s[((0))]

Cracked.

@MartinBüttner Heh, nowhere near the original indeed. But your solution is possibly even more terrifying than the original. ;)

Hey there's a fish

So the print and downcase! were red herrings. I expected the answer to use puts, did not think of $><<.

Perl - 47 (cracked by grc)
Code (there is one space in there too)
 """"$$$$$$((()))**....///;;[[]]~==01finoprrstx

Output:
012345012345012345012345012345

You can run it online here and it does work under strict and warnings.

Is this a valid solution?

@grc I'd say it is valid! Nice work! It prints the right thing. If you want some hints on the version that runs under strict and warnings let me know.

Ruby, 33 - cracked by user23013
enpsttux [[[]]]++\-\**????$$$$...

Output:
[*]

Original:

 puts ?[+[*?*..?]][$$-$$]+?\\.next

Which version is this?

@nooodl I have 1.9.3, but there's nothing version-specific about this one.

This is tough. Here's what I have so far: puts  is obviously going to be the first thing there, .next is another keyword that can be used, and the rest is some sort of sorcery with ruby $ variables and character array creation.... +1

Cracked.

@user23013 Nice! Not the original, though; I probably should have output characters that weren't actually in the source ;)

Python 3, size 16 (Cracked)
Code:
help tim__rolo__

Output (with newline at end):
Hello world!

Cracked.

@MartinBüttner I knew someone has seen the easter egg...

I hadn't, but I was quick to google it. ;) To be honest, if I hadn't been in such a hurry, I probably could have seen that the remaining characters after hello were an anagram of import. ^^

Python2, 132 characters
____        ,,,,:::''""""""""""((()))[[]]\\\0126aaaabcccceeeeeeeeeEffggiiiiiilllllmmmmnnnnnnooooopppppqqrrrrrrrrrssssStttttttuuvxxyy

Output (with a newline):
chance

Updated version, 96 characters
Answer to original version suggested the exec instead of compile+eval, so here is a simplified version:
____       :::''""(())[[]]\\\0126aaabcccceeeeeeeeEffiimmnnnnooopppqqrrrrrrrrrssStttttttuuxxxxyy

Update: cracked
Fully cracked by Alex Van Liew and KennyTM. The original solutions were (scroll right to reveal the spoiler):
                                                                                eval(compile('try: compile("from __future__ import braces","","single")\nexcept SyntaxError as q:\n\tprint q[0][6:12]',"","single"))
                                                                                exec('try:exec("from __future__ import braces")\nexcept SyntaxError as q:\n\tprint q[0][6:12]')
                                                                                The hint meant "Consider {}, which are not present in the source code".

How many newlines are there?

None (not counting logical newlines like \n inside strings literals). With newlines the code could be shorter.

+1 for not giving enough xs and cs for me to do what I want to do :P

Shall I think up some hint? Let's start with a vague one: Don't count ones which exist. Count ones which do not exist.

Cracked.

Ruby, 29 [safe]
Trying to see how short I can get in Ruby without getting cracked.
Code
paper view
otool
$()**,.8<<=>

Output
[0][0, 3][0, 3, 6][0, 3, 6, 9][0, 3, 6, 9, 12][0, 3, 6, 9, 12, 16][0, 3, 6, 9, 12, 16, 20]

Original

eval <
.write(o)
 p

Explanation

 The first line creates a heredoc that starts on the next line and is delimited by the trailing p, then concatenates the resulting string to itself 8 times. Since it ends in a newline, this effectively creates a loop. The looped code assigns an array to the variable o, consisting of the elements in o.to_a (via the * shorthand), followed by the output of $<.write(o), which converts o to a string, prints it to STDOUT, and returns the number of bytes printed. A variable being assigned to for the first time is nil for the purpose of evaluating the right hand side, so on the first run *o is empty and write outputs nothing and returns 0. Each subsequent round outputs the array of bytes output on previous rounds. Using a p-delimited heredoc creates decoy methods for output, p and $><<, in the scrambled characters, that won't work because you need the bytecount.

Perl, 36 ← cracked by grc
Code
$$$()++..112279;;<<=__ffiinooprrrt{}

Output
perl

Tested here

Finally cracked.

Haskell, 100 Chars (Invalid, output too long)
Code
//Sup
tl=[]
while(syn==(+j)) tl+=b.a();
//(: #jquery :)\\
$("#jquery").on("click", j=>alert(j==m))

Output:
"\er\\e\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"\\\\\\\\\\\\\\\\\\\\\\\\\\"\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\\"\\\\\\\\\\\\"\\\\\\\\\\\\\"\\\\\\\

Original
(#)=(>);(//)=(++)
l=j.show
main=putStr.l.l$l"eer"
j[]="\\"
j(y:u)=let(q,c)=break(#y)u in y:j c//j q

I thought for a moment that I'm reading "Evolution of Hello World" question.

@Vi yeah, but I think that the Levenshtein distance is a tiny bit more than 7 in this post.

Output is longer than 100 chars

@noodl OOPS! I had an extra period in the scrambled version.  I'm really sorry to anyone who tried to unscramble this with the extra character.  The original program does have 100 characters.

@Zaq: the size limitation is not on code size, it's on output!

@nooodl Oh wow. I totally overlooked that.  I guess that makes my submission invalid :/ I'll go ahead and post the code then

Huh. And I guessed you did something with fix show. Definately uncrackable

Pyth - 35 - Cracked
In the spirit of @MartinBüttner:
Code
"Programming Puzzles and Code Golf"

Output
4.459431618637297

Try to decode it online here.

I've cracked it, but in the interest of getting more people to use Pyth, I'm temporarily removing my answer.

Alright, cracked.

J, 22 bytes
Code
!%()1348:::bbceehorvxx

Output (97 chars)
1226317306651180983274420265228191056569220222873505571155987454033425908908110103433163350999040

I expect this to be practically impossible...

PHP, size 49 [Cracked by Martin Büttner]
Code
sub(print2w, $+expect+$+one+$+str+$+in=$@~main$);

Output
{main}

Would you mind disclosing which PHP version you tested this with?

@MartinBüttner I won't specify the exact range, but everything from 5.3.0 up will have the correct result.

Cracked. Only took like... 4 hours...

@MartinBüttner wow, congratulations! Didn't expect you to not give up. :-)

CJam, 32 bytes (cracked)
Scrambled source
"Beware the Jabberwock, my son!"

Output
4074552392882954617076720538102062920

Hm, where did you get the idea for using a quote as scrambled CJam code. ;)

Cracked

@MartinBüttner: That's a line from a poem, not a movie quote. Entirely different!

@Dennis Wait, mine wasn't from a movie either. (Not exactly from a poem, though. :D)

MATLAB, 41 bytes
Cracked by feersum
((((((snowy leopards can like magic))))))

Output
1

Cracked

TinyMUSH 3.1, 20
Scrambled:
(#ret,#3!#+#2i\2#,@)

Output:
3210

How are we supposed to run this? Where is the language reference? (The link doesn't help here).

@n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀h You can run this code by connecting to a MUSH running the appropriate TinyMUSH version.  Browse here to find one where Server Type is "MUSH", or download the server source from here and run a MUSH yourself.

CJam, 19 (Cracked)
Code
JJ2334567899#%**~""

Output
500827930823087774653348

Sorry, but cracked in the last minute.

Grass, size 134 [safe]
Code
WWWWwwWwWwWWWwWWWWwwwWwWwwwWwwwwwWWwWwwWwWWwWwwWWwwwwWwwwwWwwwWWwwwWwwwWWwwwWWWWWWWWwwWWwwwWwWWWWWwWWWwWWwwwwWWWwwWWwwwWwWWWwWwwwWWWWW

Output
wwwwwwwwwwwwwww

Tested in the Python interpreter.
Solution

wWWWwwwwWwwwwwWwWwwwwwWwwwwwwwwWWwWWWwWWWWwWWWWWWwwwwwwWwwwwwwWwwwWWwWWWwWWWWwWWWWWWwwwwwwWwwwwwwWwwwWWwWWWwWWWWwWWWWWwWWWWWWwWWWWWWWw

I wonder if anyone has tried...

This is straight up cruel. Good job.

Your program is safe now.  You should post your code to protect your submission.

Python 3, size 44 [cracked by feersum]
Scrambled:
print(((((((((((((()))))))))))))),,<<<<<<<~~

Output:
3

I'm trying to make Python look more like LISP.

Explanation

 This one relies on Python's use of implicit conversion. ()<((),) evaluates to True, and applying << [bitshift] implicitly converts True to 1.

Cracked

@feersum Fast :P

Python 2 - 61 Cracked
Code
r~s]l][]:.c[():sit_'3-'(pt_trp.l]2-~n:][.i':o:p0Te[d_u1[.')i_

Output
get

Original

print''.__doc__[::2][::3].split()[1].split('.')[0][:-~-~True]

Cracked.

Outputs s> in Python 3.4

@CoDEmanX Yes, I wouldn't expect this to work in Python 3, which is why I specified Python 2.

Python 3, length 110 [cracked by grc]
Scrambled (\n denotes a newline)
\n\n\n   ""((((())))),.......9::;===IOS[]__addeeegghiiiiiiiiijllmmnnoooooooppprrrrsssssssssstttttttttttuuuuuvwyyy

Output:
The better is Flat dense. break never of be do at never. If bad it honking

Here's another fun one - not meant to be hard, but just something unusual and puzzly. :)

Explanation

 The random-looking words are taken from the Zen of Python (PEP 20), which is automatically printed via the easter egg import this. The passage is just every ninth word, as hinted by the 9::[] present.
 To extract every ninth word without automatically printing the passage when importing, we redirect sys.stdout to a StringIO().

Cracked

JavaScript, 73
Code
console.log((((((('[[.....=-,,]]'+'02aaceeeeeefiiijllopprrrrssttv')))))))

Output
denied

Cracked.

GolfScript, 20 bytes [safe]
Code
...[[]]{{}}&%%++++5i

Output
32

Output does not have a newline character in the end.
Inspired by this comment.
Solution

.{5i[+]+}.%{}++[.%]&

Javascript, 29 - Cracked
Run in a Chrome browser console
Code
23*47,(no,(.][j,i|i,j][.),on)

Output
181

Original code

 [,,,].join(3)|[,4,].join(7)*2

Cracked.

PHP, 53 (Cracked)
Code
o3o5do=++,"oodr=f(+$fni9$d;$9=d9$$%rp7<o$t=$);$,")5(;

Output
571349220413226117734422843528553434864141775449210755731225661136475615328581707

Cracked it :-)

PowerShell 182 [safe]
but definitely not the winner
''-join%{[char]};;|$()$a$a$a$c$c$c$_===+;    0-82,-82,-75,-70,-68,-68,-65,-15,-11,-11,-11,-11,-9,-7,-7,-7,-6,-6,-6,-2,-1,-1,0,1,1,7,8,8,8,11,13,13,13,15,21,25,48,65,79,80,80,80,80,80

Output
Peter Piper picked a peck of pickled peppers

Solution
$a = 0;$(80,21,15,-15,13,-82,48,25,7,-11,13,-82,80,-7,-6,8,-6,-1,-68,65,-65,80,-11,-2,8,-75,79,-9,-70,80,-7,-6,8,1,-7,-1,-68,80,-11,11,0,-11,13,1|%{$c=$a+$_;$a=$c;[char]$c}) -join ''

You program is safe now.  You should post your code to protect your answer.

Golfscript, 32
Code
  *++..0011125::::;;;?bbbbcccc{}

Output
1993841993677373809355710590420516863199384199367737380935571059042051686311

Ruby, 43
Code
*+89*:%t(|in set{2e0--1e2}|*.prime?<~1)(25)

Output
11010100010100010100010000010100000100010100010000010000010100000100010100000100010000010000000100

Hint

 The scrambled code (after the first few characters) describes the output. For each number in the set of natural numbers between 2e0 and 1e2 (2 to 100), output a 1 if it's prime and a 0 otherwise, for 25 primes in total.

Original Code

 98.times{|e|print (2**e*~-5-1)%(e+2)<2?1:0}

Explanation

 I learned this trick from leonid's answer on an Anarchy Golf problem. The code doesn't actually do a valid prime check, it uses the Fermat Primality Test in base 2, which is probabilistic but is correct up to 341 or so.

PHP, size 23 [Cracked]
Code
echo@$b=$b.$c,$c=$c.$c;

Output
bbbbb

Ah, that was unfortunate. I've got it now, but I can't submit again.

@MartinBüttner How did you then get it now? (Do you even know why it works?)

well I just got it by experimenting a bit more. I don't get what I need the @ for, I have no idea why concatenating undefined constants work and I wasn't aware that you could have more than one $ in a variable name, but otherwise, it's pretty clear. ;)

@MartinBüttner the @ is just for avoiding notices. I wonder if there was another solution than my original, so I asked.

Yeah I thought @ suppresses errors and stuff, but it seems like the online tester I was using doesn't print them anyway.

Cracked.

JavaScript, length 32 (cracked)
alert('HaVobp'.match(/[HaVt]+/))

Output
puGiXm

Is this testable in browser console?

Cracked it!

C, 70 (Cracked)
Code
C='g'-pf;main(hx){ok,the(hot)Cake isA lie;forC*-g.=+:;prntf("%d",40);}

Output
40135

Original Solution

main(h,r){float C=h;ek:C+=0xA.ep4;if(h--)goto ek;printf("%g",C*'sd');}

Cracked

C++11, size 104 [safe]
Code
<<<<<<==>>  ,,,,,,;;:::::?.""(){}\&&##07aabcccccddddddeeeeehiiiiillllllmmnnnnooorrsssssttttttttttuuuux

And two newlines.
Compiled with g++ --std=c++11.
Output
hello
hello
hello
hello
hello
hello
hello
hello
hello
hello

I thought I should have printed something better than hello.
Solution

 #include<iostream>#\><

struct u{int t=std::cout<<"hello"<<std::endl&&7;}l,d,s,c,b,main=d.t?exit(0),l:c;

Someone please explain how it works to me...

I tried this one; I was unable to find the answer, but it inspired me to write this C program: `#include <stdio.h>
main(x) {
bsearch("hello\n", &x, 1000, 1, printf);
}`

Is there a trailing newline?

@MikePrecup Yes.

CJam, size 19 (Cracked)
Code
"Can't touch this!"

Output
hunt 12tacos

(Probably not as difficult as the last one, but I had to post a sequel.)

It's taco season - Elmer Fudd

Cracked.

CJam, 34 bytes (cracked)
Scrambled source
""Beware the Jabberwock, my son!""

Output
1.0245778622239579

Guessing its the same concept as Martin's

@Optimizer: Certainly inspired by it, but hopefully much more difficult to unscramble.

The jaws that bite, the claws that catch!

Cracked, with Martin's idea.

Ruby, 35
Code
}||{yyssplliihhddaa____][>====:.-)(

Output
shadilyshadily

Methinks the scrambled code should have ended with >:-)

Cracked.

JavaScript, 69 Cracked by FireFly
Code
grr('action rat')''(((())))*++++00001122333355566677====S[[]]ffffffxx

Output
"nananananananananananana batman"

Run in browser console (string result is REPL), tested in Chrome 38, Firefox 33, and IE11

@MartinBüttner Shoot, you are absolutely right (fixed)

Cracked.

JavaScript, 79 bytes [safe]
Another one, for fun.  Might be similar to Shawn's 69 (at least I got the idea while working on it and not succeeding).  Outputs using alert, which is already unscrambled for your convenience.
Code
alert(0123)
//((((()))))++...3566777===[[[\]]]
//accefffgggghhhhiiklmnnoorrstuw

Output
underhanded

Hint
Here's a hint: think of substitution ciphers.
Solution

 for(f
in(g=/56732106737/.source+(h=[])))h+=g.link().match(/\w/g)[g[f]]
alert(h)

 The digits in the regex pattern correspond to indices in the string g.link() aka 56732106737.  "underhanded" uses only characters reachable by indexing with single-digit numbers into this string (most from "undefined").

Perl - 26 bytes (cracked by choroba)
p:rlq{not goto p,if$a>=$b}

Output
potato

JavaScript, 31 bytes (SAFE)
Code
'([(102)])prenatal.gecko'tonsil

Output
j

Should work in any browser console, although it is a standalone program.
Original source

 alert('0acegnos'.link(top)[12])
 The characters in the string are red herring, so it wouldn't be obvious what functions were used. It uses the little-known link function, which makes an HTML  element. The top object is converted to a string as [object Window], and added as the  link, the twelfth character of which is j.

Just double-checking, is the code missing a third o by any chance?

@MartinBüttner No it's not.

Very clever... maybe try for a shorter one now?

SAS, 17 (Cracked)
%%()1;>>aabelptuv

Outputs 0

Is this actually a full program? From what I read here it looks like any full SAS program needs at least two semicolons, as well as some sort of RUN directive.

Yes it is, and what makes you think that two semicolons are needed? There's more to SAS than procs and data steps, as suggested on that page...

Just checking. I don't know the first thing about SAS, and after skimming that first section it sounded like that's the structure of any SAS program.

It is a program, and it's been cracked. http://codegolf.stackexchange.com/a/41199/32668

Coffeescript - 96
There might be more than one way to solve this one. It's also pretty long, but hopefully it will survive cracking for a while.
Output:
5299944725070263763912242111215369742359896456157909233296841284031194827848086

Program characters: (note \n is a newline and \s is a space):
j\n][j9\sa='';]4j90].[.[i\n1].=iaa[]e]9i[9\sa]\s9t][ia2]n.8v\nan.fa=ar%,i\s1%=l+o.\s[09[j],+v%[\sroj,[9i.

Or without \n and \s:
j
][j9 a='';]4j90].[.[i
1].=iaa[]e]9i[9 a] 9t][ia2]n.8v
an.fa=ar%,i 1%=l+o. [09[j],+v%[ roj,[9i.

In the scrambled code, I accidentally put a 2 instead of a 4... sorry about that. It's fixed now.

I'm pretty sure it's impossible to crack some of these submissions with more than 50 characters.

Marbelous 45 [SAFE]
Chars
^^^^^^^^^^!!&&000004459:<<<>>>\\EE//V{{{{}}}}

Each ^ is a placeholder for a newline.
Output
Z{-8H`

Source

44
{}
:{}
}0E5
<<
}0
E9
&0&0
>>\/
>V!!
/\{<{0

{} is a board that calculates (((}0 * 3 - 23) mod 256) - 27)/2. This is a Linear Congruential Generator, with its output modified to fit in the printable ascii range more often. The program terminates at the first output that is not a printable ascii character.

JS Marbelous Interpreter
This requires cylindrical boards (i.e. marbles pushed off of the board on the left reappear on the right and vice-versa).

This is safe now, so you should post your program to protect your submission.

Python 3, size 48 (Cracked)
#print(']'2p/')'\xdh))2[:roo,h+(2*e'rw)/r(d'o(()

Output
head

Hopefully this one lasts a bit longer...

Cracked. Pretty sure this is the intended answer.

C++, 192 chars (Cracked)
Code
#include<stdio.h>
#define d double
(){return ;}(){return ;}int main(){printf("%.15f",));}       %(((((()))))****,,,,,,,,,,,-----..///000011122234477777::>??dddddfffggggiiiiiiiiiiinnttxxxxxxyyy

Output
3.141592653589793

Cracked

CJam, size 15 (Cracked)
Code
6789%%%++:,{{}}

Output
882

Cracked.

CJam, size 52 (cracked)
Code
,,,,,;::::'""))@*\&%+++++333333333333333333ccffffffm

Output
0!1"2#3$4%5&6'7(8)9*10+11,12-13.14/15016117218319420521622723824925:26;27<28=29>30?31@32A

Cracked.

Java - 70 bytes
.;{({([(pentagrams are cool)])})};. Sivintilituscimt Spunsimtsbuncyndt

output:
s

no quotation marks? What sorcery is this???

Cracked

Ruby, 45
Code
%()[]./ 0123456789_abcdefghijklmnopqrstuvwxyz

Output
9410663329978946297999932

Original Code

    p %q[zyfnhvjkwudebgmacsxrl].to_i(36)/51074892

See charredUtensil's hack attempt in the comments for a great explanation. And yes, I generated the code randomly. I hoped the "pangram" approach would paralyze people with the number of options.

Cracked by charredUtensil.

Almost cracked, but not quite. And time's almost up.

Python, size 60 [safe]
Scrambled:
\n    ((((()))))***,-0123:=____aaaabdegiilmmmnnoopprrrrsttttu

Output:
1177652997443428940314

This probably still falls on the moderately-okay-to-crack side, but I thought the idea might be interesting. \n is a newline.

Solution

 The number, searchable on OEIS, is the sum of the first 23 factorials. To implement a factorial function without any ifs for the base case we use Python's short circuit evaluation and the quirk that 0**0 evaluates to 1.

 t=lambda _:0**_ or _*t(_-1)or i
 print(sum(map(t,range(23))))

Does this work in both versions of Python, or just in Py2?

@DLosc Should work on both versions. I tested on 2.7.8 and 3.3.2

GolfScript (13 bytes) (Cracked)
&+,,../224?{}

Expected output:
1234260885218145824583458445854586253225388392299142924142925142926142927142928302928497409497409

Cracked.

Marbelous, 37 [safe]
Code
^^^^^^^^!!-0002:::<<<<>>>>\F///WW{{}}

^ represents a newline; no ^s are to be used.
Output
lHp`

Original Source

F2
 >:
 :>:
 }0
 <<}0
 -W//
 <<
 >W!!
 /\{0{>

 This passes 0xF2 into the board >:, which finds 2*(3*}0-32) mod 256, checks to make sure the result is greater than 32, and if so, outputs it down and left. The down marble is emitted as a character, and the left character is passed into >: again.

JS Marbelous Interpreter
This requires cylindrical boards (i.e. marbles pushed off of the board on the left reappear on the right and vice-versa).

C, 51 (cracked)
Code
f;main(h,taxgpl) {for(c=90;c;c++) printf("%.d",h);}

Output
8065

Original Solution

main(h,dr){float c=+h+0xf.cp9;;; printf("%g",(c));}

cracked

@Art congratulations!

I was trying to abuse argc being 1, but I hacked up my solution on a machine with clang and it refuses to accept non-standard definitions of main. It was a neat puzzle. I almost gave up after I spent two hours trying to do something like c=0xfbc; .. printf("%d", c + c + 9); but there was no "b". Was that on purpose? If so, it was a great tarpit.

PHP, 44 [SAFE]
Code:
""(())46;=BFGHNOWWZ_aaabbcddeeeejjloopssvwyy

Works on PHP 5.3-5.6. A bit long, but I hope it's difficult.
Output
4096

Original code

eval(base64_decode("ZWNobyBwaGFyOjpHWjs="));
 which is the same as:
eval(base64_decode(base64_encode("echo phar::GZ;")));

Explanation

 The code will print predefined constant GZ of Phar class which is just compression constant (0x00001000 = 4096). Then the code is encoded with MIME base64 text format and eval'ed (executed). Note that base64 is data encoding format (not hashing or cryptographic function).

I wrote a script to test every program beginning with ZWNoby. But I excluded programs containing :: because :: at the wrong place would generate a fatal error, and I didn't think there is a :: in the answer...

Ruby, 33 [safe]
Code:
&(())*09:==_yogurt puns...perturb

Output:
[0, [0]]
[1, [1]]
[2, [2]]
[3, [3]]
[4, [4]]
[5, [5]]
[6, [6]]
[7, [7]]
[8, [8]]
[9, [9]]

Source:

    e=r=p *(0..9).group_by(&:untrust)

Explanation:

 e=r= is red herring filler (chosen to create the anagram "puts group_by return"). (0..9).group_by takes a block, passes each number from 0 to 9 into it, and creates a hash mapping distinct outputs of the block to the input. But instead of a literal block, I'm using the & syntax, which calls to_proc on the :untrust symbol to create a proc that "taints" each thing passed into it (which does nothing in this context), and returns the input. So each item in the range gets its own bucket. p * then converts the hash to an array of arguments of the form [key, value_array], and prints each on its own line.

Ruby, size 17
Code
$$$$--::<<>>??Wip

Output
1

Cracked. I'm really interested in the original code though. ^^

CJam, size 51
Thought I'd give this a shot!
Code
""%)))))****+++,/::@ABBBBJJSSUWYYYZZ[]____accdeimos

Output
Bond, James Bond.

Cracked.

Perl - 21 bytes (safe)
~$is^*peter**+working

(the above evaluates to 1, btw)
Ouput
65534

Original

s**$~^wkirgo*ee+print

Explanation

The code performs a substitution which is evaluated, and then the result of that is evaluated (ee). The variable $~ starts its life as STDOUT, so that $~^wkirgo evaluates to $?-=2;.

The variable $? is also special, in that it is stored internally as an unsigned short. Decrementing it by two wraps around to 65534.

Python shell: 15 chars
I had this strange urge not to include any 0's, 3's, or 7's.
11124455566899^

Output (to shell):
339018

Cracked.

CJam, 19 bytes (SAFE)
Code:
%\@_@){;_0}*__*)\15

(A few smileys survived the factory explosion...)
Output:
10120125854501259106171741725012526265263117252614371738261720339343012

Solution:

1_{_@)_@_*)\%}50*\;

Calculates and concatenates together the first 51 terms of the following sequence:

a[1] = 1

a[n] = (a[n-1]**2+1)%n

The sequence increases rapidly, but every time a[n] gets above n, it gets knocked down again by the modulo operation. Here's the same thing with spaces inserted:

1 0 1 2 0 1 2 5 8 5 4 5 0 1 2 5 9 10 6 17 17 4 17 2 5 0 1 2 5 26 26 5 26 31 17 2 5 26 14 37 17 38 26 17 20 33 9 34 30 1 2

QBasic, 42 bytes (Cracked)
I am having way too much fun here.
Code:
FAIR
N=PATERN"QBasic!"TIME 2 OR 1+1
HOUT N

... including 2 newlines.  (This is written in a new dialect of QBasic that allows you to use nonstandard English, redundancy, and misspelled keywords as long as you tell the compiler that it's all FAIR.)
Output:
QBasic!
QBasic!

... including a trailing newline.

Cracked.

SAS, 28 (SAFE)
%1(STAR)SPY,&2STUD;BUNNIES,%

Outputs I
(that's capital letter i)
Solution:
%PUT%SUBSTR(&SYSENDIAN,2,1);

Which outputs the second character of the automatic macro variable SYSENDIAN (which takes the values BIG and LITTLE) to the log.

Going to give this one more day, then add the solution.

Well, I'm safe.

JavaScript, 28 Cracked by Martin Büttner
Since my other submission was cracked, here's another.
Code
eval(atob('[every thing]'));

Output
1

Run in browser console (result is REPL), tested in Chrome 38 and Firefox 33

Cracked.

JavaScript, 46 characters [Cracked]
This one is easy, so I expect it to be cracked quickly.
Code
//terser code..
alert(the union fears dwarves)

(includes newline)
Output
ordered

Cracked.

Python 3 - size 34 [cracked by FireFly]
Scrambled:
print(....__str__)
[[(4,)=={-6}]];

Output:
.

The scrambled code runs fine, but it's not what you want ;).

Intended solution

Awkwardly, my red herrings backfired on me, and I only realised a few minutes after posting.
The intended solution was:
_={};_[6.,...]=_
print(str(_)[-4])
If we print out _, we get:
{(6.0, Ellipsis): {...}}
If you add a list or a dictionary to itself in Python, the string representation replaces that part of it with ...! Yes, that means you can do things like:
a=[]
a.append(a)
print(a[0][0][0][0][0][0][0][0])

:)

Cracked. :)

Ah... I should've thought of that too.. since I've seen similar things (recursion detection) in other pretty-printers. Didn't occur to me that it'd be represented with an ellipsis. Nice one, too bad about the not-so-red herring.

Mathematica, 73 72 bytes [Safe]
(I miscounted the bytes when I made the post.)
Code:
""""#&()*,,01>@@@@@[[]]`StrongSolemnNiceLustyTensorSextetNastiesEastCamp

Output:
0.5 + 14.1347 I

Original code:

N@(ToExpression@Last@Select[Names@"System`*",StringCount[#,"eta"]>0&])@1

Java, size 134 (Cracked)
Code:
"''"{}{}[]()()()()()() <<<<<<< +++-===^ ..;;;; 11113444578999 aaaaabcccccdefgghhhiiiiiiiillmmnnnnnnnnnooopprrrrrrrssssSSStttttttttuuvy

Output:
^74
^376
^2280
^17512
^139368
^1114216
^8913000

What's the whitespace in the output? A trailing \n / (char)10 on each line?

@PeterTaylor a trailing newline, yes

There are only 134 characters in the list. Is there some missing whitespace?

@feersum Oops, my texteditor gave me a wrong number :/ fixed

Cracked

J - 14 char
Going for the gold. Edit: I have been recently made aware that this code performs differently depending on whether you are using a 32-bit or 64-bit version of the latest J (j803). If this is grounds for disqualification, let me know: otherwise, I would concede a crack as an unscrambling that gives the correct answer on at least one of the two versions.
Scrambled:
7*8..?56!/x\+/

32-bit output:
2704156

64-bit output:
2722721

Does this code always produce the same output? (I'm no expert in J, but I thought ? was used to generate random numbers)

@squeamishossifrage Yes, that's correct, and yes, it always produces the same output.

I suspect the fact that it makes 2 different answers has do with the fact that the answer is really big, which would make sense if it uses factorial.

ASP/ASP.Net - 14 [SAFE]
Code
<%=Len('12')%>

Output
1

Answer

 <%=1)''Len(2%> (Basically the equivalent of writing <%=1%>)

Python 2, 29 bytes (cracked)
(.;i;=)de mnoprrrsssssssttyyy

No output.

Cracked.

JavaScript, 26 (cracked)
later(103>(8-9)&80>4|10>9)

Output
999

Cracked.

PHP, Size 14 (Cracked)
aaaaaa:::::??;

Prints nothing when notices are turned off (no warning or fatal error messages).

Cracked.

@PleaseStand Wrong link — try this instead

Golfscript - 20 (Cracked)
"open world thrill!"

Output
hello world!

Cracked.

Lua 5.2.3, Size: 18 chars (Cracked)
pghmint(rat.hue)<3

Output:
true

Cracked.

Correct. Just saying that because you didn't get a chance to test it.

JavaScript, 61 (Cracked)
Code
x=next facile tortuously inept encrypter.{}()()()()(4-1);;ffo

Output
ring

Pretty sure that the last t is supposed to be o instead. Please correct me if I am wrong.

Cracked based on the above assumption. If my assumption was wrong, I will remove the answer and this comment.

You're correct. Sorry I really messed that one up trying to be clever with the anagram.

Heh, no issues. I knew that the only way to get String is with two typeof on a function.

FYI the original used typeof(typeof 1)

APL, size 17 (Cracked)
Code
, (())****\+33333

There is a space
Output
27 3 3 4.434264882430378e+38

Tested here.

Cracked. Finally.

CoffeeScript, size 25 [Cracked]
Code
the terse tales // [.]

Output
false

You can try it out here in the "Try CoffeeScript" tab.

Cracked.

Python 3, size 37 (Cracked)
Code:
int(22 ** 2 ** 2+range(irr)[]__npof_)

Output (space separated):
0 1 4 9 16 25 36 49 64 81

Cracked.

@xnor Sorry, nope.

@matsjoyce it is now, see the comments.

ECMAScript, 26
Run in a Chrome browser console
Code
$( convenient )({"awful"})

Output
$ {}

Should I run it in Console ? Does it require Jquery to be on the page ? Please mention these in your post.

@Optimizer running in console is correct. I choose not to answer your second question because knowing that answer is something you can answer this without.

Cracked.

@MartinBüttner Nice work!

Ruby, 49 - cracked by nooodl
Turned out a bit on the long side, but I still like it. ;)
<><>
<><>
<><>
<><>
<><>
%%%% $+?;
""""""''''''''

Newlines are significant. Output:
'
""

Original:

 $><< <<'"'+?"<<<<"'";<<'%%'
'
"
"
'
>>>>>>>>>'
%%

cracked

@nooodl Aww, all that work with heredocs for nothing. :)

Marbelous, 36 (Cracked)
Code
_________^!!00039:=>\CDD/OO++++rr{{}

_ represents a newline; _ is not to be used.
Output
1110000000011111111000000001111111100000000111111110000000011111111000000001111111100000000111111110

Original Solution

9C
Dr
+O
+O
:Dr
}0
=0
!!++
^3/\{>
{0

JS Marbelous Interpreter
This requires cylindrical boards (i.e. marbles pushed off of the board on the left reappear on the right and vice-versa).
This one should be much easier to crack than my previous Marbelous answers.

Cracked. I have to say, this was one of the more fun ones to tackle. :)

Mathematica, 18 (Cracked)
Code
!!#&,-./02>@D[]ddd

Output
-EulerGamma + Log[2]

Cracked.

Haskell, 48 (safe)
Code
pencil=runner.vwxyz='a winter squirm upturn...';

Output
[""]

Solution
-

main=w 'v'; w=print.uncurry seq.unzip.lex.return

is there a newline at the end of the output?

Nope, there isn't. Note the final ; though.

Python 2, 69 characters
Output:
tab

Code:
temp[}s::nn) a ](r{mnrottr]e[p_[[3wf3sa]osi(_(;i)ttinb y.s)a]a_)_:n(_

Original

 As I don't have enough rep to comment, the original was:

import tabnanny as __;print(__.format_witnesses({():[]}[()])[3:][:3])

Cracked.

I think you can always comment on your own posts, but editing the original into the question is a better idea anyway.

C, 53 bytes [Cracked]
Code
{{(nr:xxx)()(fmax(~n,*x%-9));puts("strix siren?!");}}

Output
58980

Cracked.

PHP (>= 5.3.0), 52 (cracked by bwoebi)
Code:
 $$(((())))*+++,12345:;;<<<@@___cfghiiiinooopprrrttw

Output:
abcdefgh

Original:

_:print_r(chr(3*pow(2,5)+@++$i));if(@$i<4<<1)goto _;

Cracked

Python 3, 37 bytes [cracked by Bhante Nandiya]
Scrambled:
""((((()))))....abefiilllmnnprrssttuz

Output:
433

Trying some shorter Python submissions. Tested on Python 3.3.2 and Pypy3 2.3.1 (just in case).

Explanation

 Solution : print(sum(b"a".zfill(len(str(...)))))
 Uses the b"..." notation for bytes, which unlike strings can be summed and also the ... Python Ellipsis object.

cracked

Perl 5, size 27 (cracked)
print(rar(pizza))=~--'tanz'

Output:
ohm

Works under use strict.

cracked by  Wumpus Q. Wumbley print'pin'=~tr(a-za)(za-z)r

Python 2, 101
Code
"rne) n(sxx+ai(cpi)% ( *2n+f 1 )corii\.5n /r +5xeini+"h(5te4437f3)xjxo2]2or[)%(#"g r"+"lf/r2 # 1xn"h5
Output
'4
[#
;4
E4
##
Y4
c4

I can match the output but for one character. :( It feels like I've tried everything, but I'm not even sure if I'm close to the intended answer. I give up now. Please feel free to call this safe. I'm really interested to see the solution.

Ruby - 58 (Cracked)
puts 00000000111222344455556677888889^^^^aacdddddefffxxxxx

Yeah you need to xor the hexadecimal literals in this one...
Output:
1436068433

Hope this lasts more than my last one...

Cracked :-) How long did the last one survive?

@squeamishossifrage 2.5 hours… It lasted even shorter than the last one ;-)

Ruby, 37 (Cracked by DLosc)
p00t1s ^u^110222333444555666777888999

A lot like my other ruby answer, but this time with normal numbers :)
Output:
6809101718

I believe this type of answer is uncrackable without brute force, if you can prove me wrong kudos to you! :)
Apparently not... Kudos to Squeamish Ossifrage :)

Now it's cracked. ;^)

Brainfuck, 118 chars [cracked by feersum]
Scrambled:
[>.<]++++++++++++++++++++++++++++++++++++++++++++++------<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>[[[[[[[]]]]]]]

Output:
q$V4yQ!

This won't win, but there just had to be one. Assumes no cell wrapping, and works even if the tape has no cells to the left. I don't know how BF is scored, so I've put down chars.
For a BF program, 118's not that long...

Explanation

 The intended solution was ++++[>++++<-]>[>+>>>+>>>>+<<<<<<<<-]>>+++++++>+++++>+>+++++[>++++++++<-]+++>>++>[[<[>>+>+<<<-]>>[<<+>>-]<-]<]>>>>[+.>]. The ASCII values are [113, 36, 86, 52, 121, 81, 33], from which we can subtract 1 to get [112, 35, 85, 51, 120, 80, 32]. This can be achieved by building the numbers [16, 7, 5, 17, 3, 40, 2, 16] then multiplying pairwise.
 However, as feersum points out, this is completely irrelevant in BF as long as you can golf your code down to be short enough.

The code looks like a robot shooting lasers from eyes to a steel wall! :D

Cracked

C, 30 (cracked by feersum)
Code
_L%"p;at(_N()m_Enin{_}diIf)",r

Output
1

Cracked

Rust + Clojure, version 2 [SAFE]
This is the second version of the task. The first version is here.
Output, without the newline:
1283691742071510101818513212188161611241111219191910762714142222223591109301717171051225

There is a hint (the same as in version 1):
tr/gio_.ocupkzwwaaeeeeiiC/.ojdtkrnnlliic

Now the task is more related to the hint compared to version 1. The algorithm is the same in Rust and Clojure versions, there are no comments, unused identifiers thow-away assignments. All identifier have 1-character names.
Rust, 118 characters
====>        -,,:!/""((((((())))))){{{{{{{}}}}}}}*%+++001111112235aaeeeeefffffgiiiiiiiiillmnnnnnnnnoprrrrrrrrsstttxxxx

Clojure, 106 characters
==                /(((((((((((((((())))))))))))))))[[]]*++00011112235adddeeefffgiiiiimnnnoopqrrrrrrrstxxxx

C, 128 characters
<=====       ,;;;;;;;/""((((((((())))))))){{}}*%%+++++001111112235adeeeffffiiiiiiiiiiiiimnnnnnnnnnoprrrrrrrrrrrrrttttttttuuuxxxx

Haskell, 83 characters
======||      _;;....((()))[]$*+++011111122349aaddehiimmmMnoopprrrrrrsSttTuuvwxxxxx

Perl, 97 characters
=====   ;;/..(((((()))))){{{{{}}}}}$$$$$$$*%+++011111122349beeeffffhiiiiiillnoprrrrrrrssssttuxxxx

Shell, 170 characters
````````==                                 ;;;;;;;;;/((((((((((()))))))))))[[]]{}$$$$$$$$$$*%+++0111111111122349cccddeeeeeeeeeefffffhhhhhiiiiiiillnnnnnoooooopqrrrrrrssttt

Checked with dash, bash, ksh a zsh.
Original source codes
⚠Note: without >! spolier marks.⚠

    (the code is immediately visible below)

⚠Note: without >! spolier marks.⚠
Rust
(does not work anymore with modern Rust)
fn x(r:int)->int{if r==1{1}else if r%2==0{x(r/2)+1}else{x(3*r+1)+1}}fn main(){for i in range(1,50){print!("{}",x(i))}}

C
int x(int r){if(r==1)return 1;if(r%2==0)return x(r/2)+1;return x(3*r+1)+1;}int main(){int i;for(i=1;i<50;++i)printf("%d",x(i));}

Perl
int x(int r){if(r==1)return 1;if(r%2==0)return x(r/2)+1;return x(3*r+1)+1;}int main(){int i;for(i=1;i<50;++i)printf("%d",x(i));}

Clojure
(defn x[r](+ 1(if(= r 1)0(if(=(mod r 2)0)(x (/ r 2))(x (+(* 3 r)1))))))(doseq[i(range 1 50)](print (x i)))

Shell
r(){ if [ $1 = 1 ]; then echo 1; elif [ $(($1%2)) = 0 ]; then echo $((1+`r $(($1/2))`));else echo $((1+`r $(($1*3+1))`));fi;}; for i in `seq 1 49`; do printf `r $i`; done

Haskell
x 1=1;x r|mod r 2==0=1+x(div r 2)|True=1+(x$3*r+1);main=mapM_(putStr.show.x)[1..49]

Hint
echo 'http://en.wikipedia.org/wiki/Collatz_conjecture' | perl -pe 's//\n/g' | sort -R | tr -d '\n'; echo

Characteres were manually moved around to make it appear like a character substitution command, which is a red herring.
Explanation
Here is readable modern Rust code:
fn x(r: i32) -> i32 {
    if r == 1 {
        1
    } else if r % 2 == 0 {
        x(r / 2) + 1
    } else {
        x(3 * r + 1) + 1
    }
}
fn main() {
    for i in 1..50 {
        print!("{}", x(i))
    }
}

It prints 50 elements of https://oeis.org/A008908 glued together. Algorithm is the same for all languages.

Interactive Python 2.6, 15 (Cracked)
Code
(33*(4*12+4))/1

Output
270379522836753144265438496266566370136712020517640818813356355859028442008312225243036620289437521825508656065633888910684906390684337129360048186258048309000927118105125771665297425865729520809425997055097487267500801951307326211801132325770579267579825036033131104326181952588158139706361336195297731164624948083473959541919960343244739151223433852746136342590068225162166489275334797736589658479803522799496232002081568176260061240500941862631613470208955583641209766953178421429600070039361764538653961951816L

Original code

(43**314)/(2+1)

Please indicate the version of Python (unless you have tested on both versions and it works on both). This seems like Python 2, since there is a trailing L.

Sorry.  I updated the header.

Cracked

The output should be no more than 100 characters long...

Oops!  Mea Culpa.  My apologies.

Python 2, 13
This one might be very easy for some; for me it came as quite a surprise.
Code:
print (70-70)

Output:
49

Cracked

Super easy. Also, you could've used a python shell and cut that down to 5 characters: 70-70 Example: http://repl.it/

RPL (Reverse Polish Lisp), e.g. HP48, 24 characters (Invalid)
Code:
$ 122 / 73 CNT » + $ I «

Output (what goes onto the stack after running the code):
"$123"

It's been 7 days, 4 hours and a few minutes. The solution is:

    « C$ 3 $12 7 2 / INT + »

Agh, it's been too long! And I don't have my calculator with me. Have a +1.

Who compiles the list of Safe Submissions? I tried to add this puzzle to it by editing the "question" of the thread but my edit was rejected. If my puzzle does not belong on the list because it was disqualified for any reason, it would be nice if I was told that was the case and possibly the reason.

I suspect it's because it uses non-ASCII characters, as mentioned on your second submission. Too bad there isn't a dialect of RPL where you can use << >> instead.

@DLosc Yeah, I suspect the same. As no one looks here and because the issue may be relevant to many other languages, could you please comment to the question itself and ask what the situation is when a language requires certain non-ascii characters - does that mean that language is excluded from this Cops and Robbers contest? From reading the comments the rules were evolving after the contest started. I would have raised the issue myself but I can't comment yet because I'm a newbie to StackExchange.

I'm pretty sure that's right: a language that requires non-ASCII characters is excluded. Otherwise, there would surely have been submissions in APL and Sclipting by now. Sorry! Full props to you for your RPL skills--even with the unscrambled code, I still don't know how this works. ;) What does C$ 3 do?

@DLosc There have been something in APL anyway.

That's an alternative string notation to quotation marks: " 234" is the same as C$ 4  234 (note 2 spaces between 4 and 2). C$ is followed by space, string length, a single space and the string characters. Useful when the string contains ".

Marbelous, 55 (Cracked)
Code
________&&--......./0000000000001111111111:<<=@@@@\{}}}

_ represents a newline.
Output
t"

JS Marbelous Interpreter
Unlike many of my other Marbelous cops, this one does not use cylindrical boards.

Cracked.

Mathematica, 31
Code
PowerMod[123456789,123456789,^]

Output
1617298209804017979868926932743750272386265163887231542207613855504645035580118031906932144113367511

(Inspired by xnor's Python cops a few submissions above)

I suspect PowerMod is a red herring or you've done something extraordinarily clever, because you need to generate a number at least as big as the output for the mod bit. That being said; I count 101 characters in the output, and that's two characters more than allowed.

The ouptut is exactly 100 characters long, which is allowed. The code and output are correct as stated.

I must have miscounted, then. I got 101 when I fed it into wc -c.

@AlexVanLiew It is not easy to feed into wc -c directly without the trailing newline.

PHP (46 bytes)
Here is another attempt, but now using PHP.
The scrambled code:
print($a=Y<$dY^r^$o0);($e++)or($heY+Yo);c5+f0;

You can run the scrambled version, it will output 0.
The unscrambled code outputs this:
171819202122232425262728293031012345678910171717171717171717171717171717171717171717171717

Have fun with this one :)

Revealing the answer:
More than a week has past (I submited this at 8th November 2014, today is 17th), and here is the expected answer:

    for($Y=a;$Y^$t++<50e0;$Y++)echo(ord($Y^prin));

For the invalid answer, it should be this:

    for($Y=a;$Y^$t++<99e9;$Y++)echo(ord($Y^prin));

Thank you for not cracking this one :)

Old submission: (invalid because 1,4889251×10^77 Yotabytes is over the limit of 100 bytes)
The scrambled code:
 print($a=Y<$dY^r^$o9);($e++)or($heY+Yo);c9+f9;

You can run the scrambled version, it will output 0.
The output that the unscrambled version produces:
I'm really sorry, but the output won't fit here.
But, for purpose of testing, you can remove ONE e (Unicode Character 'LATIN SMALL LETTER E' (U+0065)) and ONE 9 (Unicode Character 'DIGIT NINE' (U+0039)).
By removing it, the output is the following:
17181920212223242526272829303101234567891017171717171717171717171717171717171717171717171717171818181818181818181818181818181818181818181818181818191919191919191919191919191919191919191919

There is NO FEASIBLE WAY TO POST THE CODE, since the code generated would be 1,4889251×10^76 Yotabytes long (Byte units, Google calculation).

C, 44 bytes (Cracked)
Code
main(){while(-n&&banana);printf("%a",n[1]);}

Output
abb

Might be too easy, but maybe not.
Original solution

an;main(){while(printf(&"a%nb"[an],&an)-1);}

Cracked

Python, 28 (Cracked)
Program: i(b)t14i])2*2tni*(pr2[3:n(n)
Output: 100220321420320200100

Cracked

Ruby, 27 [safe]
Code
co-opt value("*222555;==^")

Output
"4"

Original

 eval"putc o^=22;"*(55-o=52)

Explanation

 Calls putc three times with the character codes 34, 52, and 34.

RPL (HP48), 10 characters (safe)
I thought RPL was out of the question, as discussed in my first and my second (deleted) submission. However, instead of creating a program object (with code enclosed in « », and possibly store it), I can just type the RPL code without « » and press Enter to execute the code immediately (kind of command line).
For example, instead of creating the program « 1 2 3 + », I can just enter 1 2 3 + for immediate execution, and the output (addition to the stack) will be:
1
5

Now to the actual (reworked) puzzle that actually follows the rules. Because previous one did not follow the rules, the time for it starts now. (Unfortunately I can't post the other reworked puzzle now because I had already supplied the answer.)
Code (to be entered for immediate execution):
"DO PURGE"

No output (no change on the stack), also no error.
Edit: I'm sure I've given enough time since helping with emulator information and documentation. So I'm now claiming immunity by posting the solution:

 "GUE" DROP

Words DO and PURGE are the actual commands and I chose them because they deceive but provide the characters needed. PURGE will cause an error unless there is a name of an existing variable on the stack. Even if that's satisfied and the name is then taken off the stack, how will you get rid of ""? And how will you put a variable name on the stack without ''? It works if the variable doesn't exist, otherwise it gets evaluated. Of course, the behaviour would then depend on other factors, which should not be the case with any code in this contest. DO is for loops and would be incomplete, therefore cause an error (either run-time or syntax).

It's been about 8 1/2 days without any attempt being posted. In fact, for the last 10 days there have been no robber attempts at all. Is that the end of this pair of threads (and the contest)? I'm thinking whether I should post the solution and claim immunity as it doesn't feel like much of a win in complete absence of robbers... Also, this submission is not mentioned in the list of unsolved ones - does that still count?

Are there interpreters/emulators or documentation for this language available online?

Yes, @algorithmshark. I've seen the emulator on Linux, I've got the Android one, there's plenty to find by searching "hp48 emulator". I'm pretty sure it's available for all major platforms. Here's the manual straight from the horse's mouth. Should I (with the spirit of this contest) extend my immunity claim to give people a proper chance as I have only just offered help with this comment?

Python 2, size 23 [SAFE]
Using http://repl.it/
Scrambled
-/*[st0r3:.1245689])(()

Output
'110665.1105651'

Original Code

(str(065/.814)*2)[9:-3]
This takes the octal value 065 and divides it by .814 to create a longer decimal value. I then converted that to a string and repeated it twice by using *2. The final part takes a substring of that result, making it harder to know what went on.

Python - 37
mr79ltmo22mat51p*h(* .ian tpihgt)or()

(NB: there are exactly two trailing spaces)
This is both easy and hard at the same time.
This program
+Returns 1975
+Does not error or throw any warings
+Uses all of the characters (no print(1975) for you)
As a bonus challenge:
(t.nmm)t(= (ihn ))tttu*oaniiorm(tignp2hlpa) npr * 2

(NB2: trailing space)
This takes in a number n as input and returns it, with no errors/unused characters.

Mathematica, 29 (Cracked)
Code
FPP$cur[int]ion,retn;{2x=5+2}
Output
5
I ran this in the math command-line tool, but it works just as well in a notebook.

Cracked.

CJam, 18 (Cracked)
Code
012234567889""**%~

Output
444

Cracked.

Python, 68 (Cracked)
Code
"""""""""#''''''(((((()))))),,,,,-0235;==CYbcdehilnooooooppprrrsstt{

Output
#123456789

Cracked - Think this should be the intended solution, or something similar at least

PHP, 52 (Cracked)
Code
$)6am;crcn--+i(shr_4;9(na(%d_ ))t$2)o5tmrd(frhieo3=;

Output
Wu]w.iB ZKlXV=(mYz(z,b,IlZ+Vi.J!5wMM6Dfa4N4^=]

Cracked!

Vi.?

Python [both], 154 characters (Cracked)
Code
""""%(((((((()))))))),,,,,-...////00011111133355888==[[[[]]]]            ________aacccdddeeeefffffghiiiiiiiiiiiiijjjjjllmnnnnnnnoooooooppprrrrrrrrsttttuuu
That's twelve (12) spaces.
Output
ruby

Does "both" mean that the code needs to work for both versions of Python or just 1?

nvm, cracked

CJam, Size 12
Cracked by user23013
!mop[ET_^~+1]

Output
-214

My first ever CJam program. :)

Cracked.

Python 3 size 54 (Cracked)
(o'd)'op'/r),2\x'12.)w/)h],c'dp*((rx:(h('r'ol'ae#)[ere

Output
'head'

Does this have a print statement included or is it supposed to be run in a shell?

Run in a shell. No print statement.

Solved.

That works. Forgot about that pesky 'a'.

Java 6+, 101 bytes (Cracked)
Works on Ideone
class t{public static void main(String[]a){short free=420;System.out.println("'t'p't'(d);;++=>/|");}}

Result:
1274127634633143115415747343141

Mostly unscrambled for ease of cracking. :)
(No it doesn't output 't'p't'(d);;++=>/|)

Cracked

Rust, 123 characters
"{{{{{{{   -   }}}}}}}  > pgttts* ==== (((((%00xxeee,,:  +miiiiiiiiii  999aa   222222!  nnnnnnnn  /o1)))))  lffrrrrrrr3fff"

Output, no newline at the end:
97584

You may use Rust Playpen for experimentation if you don't have Rust installed.
There is a hint:
tr/gio_.ocupkzwwaaeeeeiiC/.ojdtkrnnlliic

Clojure, 96 characters
(*(((+((([]  (((=(=(( /[0]012222223999 adddeeeeffghiiiii  mnnnnoopq  rrrrr   rstwxx)))))))))))))

Same output, same algorithm, same identifier names, same hint.
Update
This version is solved. I have posted the version 2.

Are warnings required / disallowed / irrelevant?

Original code does not produce warnings. It also does not contain comments, throw-away assignments or unused identifiers.

Rust part cracked.

Python 2 - 38 Cracked
Code
lp[__et._i(ri`2(]-:)pn1[s:)]t~i]t.`r[_

Output
beta

Now with 100% less '' ;)

Cracked :)

PHP, 13 - Cracked
Code:
abcde(())@i;_

Output:
abc

Original:

 die(_(@abc));

Cracked. ;)

Javascript size 13 (Cracked)
Going for the shortest, runs on shell
([[])+]+[-}{]
Output
"0"

The question asks for programs. I'm not sure about the Python submission, but the JavaScript seems to require a shell. I don't know if that is allowed. (Also, different submissions generally go in different answers.)

@Dennis Both of them go into shells, I split them up.

I count 13 characters. (And cracked it.)

Haskell, 42 (Cracked)
gS{int S;S{ Shin=pr}=Sta S=vinow;mari}deda

output
S

original code:
data S=S{}deriving Show;main=print S;S{}=S

cracked

Javascript, 82, [Cracked by Shawn Holzworth]
Run in browser console, tested on Chrome 38
Code
bbbbbbbbbbbbvv'''' 00001245667799[[[[[[[[[[[[((=+++++++/=/++++++=))]]]]]]]]]]]];;

Output
u never find

Cracked

I tried cracking a few, but, NP-stupid-hard that this is, I didn't succeed.
Instead, here's a C program:
C, 39
Code
&&''((()))++9;;;<^____aaachiimmnnprtu{}

Output
_^]\[ZYXWV

This would be easy if I could rotate < into >.

Cracked

CJam, size 13 (Cracked)
Code
,/*#%CEffGIKs

Output
030819828850379075460427536222159187897761502517030034671154875945928930530907551421904962649729

I think this should be hard without brute-forcing.

Cracked.

C++11, 121 [SAFE]
Code
#include <iostream>
#include <cstdint>
using namespace std;
main(){{uint64_t b=-1,to(+'.');int uavlq(b);cout<<b-to,'d';}}

Output
2901942

Source

#include <iostream>
#include <cstdlib>
using namespace std;
main(){auto t=div('_nnt-',641);int b{'-,'};cout<<(t.quot+b);}

Note that the answer uses cstdlib, not cstdint as given in the scrambled version.

uint64_t does require C++11....

I lol'd at swapping cstdlib for cstdint

Little Man Computer
63 characters long.
Cracked by feersum [link].
This one may look overwhelming, but it's really easy to crack.
You can find an online emulator (that uses Javascript) for LMC here.
When writing the source, I made sure each "box" I used was padded to three characters with leading zeros.
Source (original)

Source (scrambled)
550780299002200104931956059169005996800195499090005297333101782

Output
51

Cracked, I guess.

Javascript, 30
(())M^aaaehhiilmmnrtttwx

Output:
0

Cracked.

C, 48 (Cracked)
Code
main(fma){fma=(0.9-'gpfx'),printf("%ddel",fma);}

Output
-1378246

Original Solution

 main(f){f='ma'-lgamma(0xfe.dp9),printf("%d",f);}

Pretty simple.

my attempt. I don't like it very much, but it fits too well to be a coincidence.

Python, size 41 [cracked by DLosc]
Scrambled:
""(())****666;;;;====ceeinprtxxxxxxxxxxxx

Output:
134713546244127343440523266742756048896

Since my short submission got cracked, I thought I'd submit a shorter (and fixed!) version of another one I currently have up. This might make it a lot easier, but who knows.

Cracked. That was fun.

DC (28) (cracked)
Code:
++01111<[]ddlllnnnnsssssssx

Output:
13610152128364555

Source:

 Original: 1ss[lsd1+ss+dn11ls<n]sn0lnx
Cracked:  [ls+dn11ls1+dss<n]sn1ss0lnx

Explanation

 This is made up of a macro [ls d 1+ ss + d n 11 ls < n] that is stored in register n.  It loads the value from s, duplicates, it, adds 1 to it, stores that value back in s duplicates the value on the stack, prints that off (n is the print without return), and then compares register s with the value 11.  If the value that was in s is less than 11, it invokes the macro stored in register n.  A value of 1 is used to initialize register s and 0 on the main stack.  The macro n is then loaded and executed.

Sequence with spaces:

 1 3 6 10 15 21 28 36 45 55

Cracked.

QBasic, 43 bytes (Cracked)
Code:
GRANT EACH SAME;
DIST DAPPER 6;
ID$3
PEEP??

Includes 3 newlines.
Output:
??
(Output is followed by a newline.) Tested on QB64. I'm quite positive this won't work on Repl.it or other online QBasic interpreters.

Cracked.

C - 43 - Cracked
Code:
_main(_,su){_printf(&1+1+1+'1'),_TEA[0xD];}

Output
4

Tested with gcc

I've got a rather klunky solution for this one.

@Allbeert: I think your submission should be disqualified, since it produces different result at different time (even if it takes weeks to for the result to change).

@n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳  Agree. I actually missed the "regardless of when/where it is run" requirement. However, since it was already cracked, I think deleting this answer at this point will not really be productive.

Perl, 39 (Cracked)
Code
//shredding($c_)=\\t_;$_=($r/~$p*2014);

Output
H

Tested here

Cracked with help from chilemagic.

ECMAScript, 29 (Cracked)
Code
1("HAlf PEnCesEveNthswunG".5)

Output
32768

Both this and your other submission seem to require a console/REPL environment, and are not full programs.

You're on your way to cracking them if you see it needs a javascript console. The definition of full program is important.

I'm not sure how to understand that. I do have a solution that works in the console now. Is that valid, or is there an answer that does not rely on the result of an expression being printed automatically?

@MartinBüttner if it works in the console it's valid. I wouldn't preclude a solution I haven't imagined also working.

Cracked.

@MartinBüttner Nice! [point of interest I used PushEvent].

PHP, Size 30
hill_top_101_(at)merchant.net;

Prints nothing with no errors, even when E_NOTICE is on.

What's that? Move the @ to the beginning and finished... This should be a challenge...

I overlooked something... will edit in a minute.
Edit: seems like since my old PHP version @ behavior has changed. But it's useless to the challenge anyway.

Cracked [that one is easy when you know the primitives to stop ;-)]

PHP, 44 (cracked by bwoebi)
Code:
 $$(())07;;=@[]____aacddeeeeghhilmnoprsssttw

Tested different PHP versions.
Output (default for PHP 5.3.x, 5.4.x & 5.5.x),
valid

Tested on terminal (-r), PHP file and online here.
Notes:

You need at least PHP 5.3.0 or higher.
In some on-line testers it shows some warning, as it ignores @.
In some online testers it seems the output is seek instead for some reason (here), not sure why. At the same time it's a hint.

Original:

@$_=get_class_methods(new phar);die($_[70]);

Cracked

Mathematica, 35 characters (Cracked)
Code
'Pen & Pie Part Preprinters'====$$;

Output
0

Cracked.

Lua, Size 49
=x)f+ nir  +opxdnx5x7 e+ = =0)rx(d1.*1t)x1o(,(i21

Output
1103219.5489201

There are 6 spaces and no newlines. I wrote it in Lua 5.1.4 to be specific, but it should work for any version.

Lua (again), length 28 -- Cracked
There are no newlines, and 1 space.
hit).na.iat1 aai=an(ms(p)r*p

Output
4.9348022005447

Cracked.

ECMAScript 6, 116

Code
1na.M.))wg)iae/l)2e(s}w1(wowo((s*)r7Ean p.(),e,t?=1ttulh+gnoed+lol>(.ccEe(1ui,+t2e-2(m,ean+eeh(.)2o1a/e:{a)-re7r3)e6
Output
747135.7188700009

Javascript: 47 chars (Cracked)
//if("rest")("it will tell a surprise tale!")()

Output:
a surprise!

PS: My original snippet does not contain any comments. Whoever takes a shot at this, try to crack that version.

Cracked

Cracked without comments.

PHP, 33 (cracked by squeamish ossifrage)
Code:
(()),01;<=_eggghhhiiillnnrrssttt?

Output
52

Original

<?=strlen(highlight_string(0,1));

Tested on all PHP between 5.2 and 5.5.

Cracked

Python, size 41[cracked by nneonneo]
Scrambled:
" "(()).01A\[]____aceeeeiillmnopprrrrttxx

Output:
search

Tested on CPython 2.7.8 and 3.3.2, Pypy3 2.3.1 and Ideone. I'm not sure whether this is really easy or really unfair.

I've got a subset of the characters that prints search on Python 2 but I can't get rid of the other ones...

@feersum That's interesting... I think I've copied it right without any spares though

I certainly don't think it's the same one. I tried it on Python 3 and got a different result.

@feersum Hmm well if you can get it working somewhere verifiable (e.g. Ideone) then it should be okay

Cracked. For me this falls in the "really easy" category.

PHP, 21 (cracked by PleaseStand)
Code:
<?=9*8*7*6*5*4/3/2/1;

Tested on PHP 5.6.
Output
14348907

Original

<?=9**8/3;/**124567*/

Cracked.

JavaScript, 42 Cracked by Optimizer
This should be pretty easy.
Code
tu curt infernnnnnnnnnno!(((())))+--58{||}

Output
1712

Run in browser console (result is REPL), tested in Chrome 38, Firefox 33, and IE11

Cracked

Java - Size 97 (Cracked)
Code
""''{{}}(((())))...345:;[]^_     BSSaaabbbcccdeeeefgggiiiiiiillmmmnnnoooprrrsssssstttttttttuuvwyy

Output
X^Y

note: ends with a newline

Cracked

Ruby, 23 (Cracked)
code scramble:
[[d++]8%-0]the...11 mops

output :
"lice"

tested on: http://repl.it/languages/Ruby/

Cracked

CJam, 47 bytes [safe]
Code
###'''(())**+-0112333479:KKKKNNN]__cdffmtt{{}}~

Output
316218750702865:484776333:983474443201156009:7420206870:545426587396511674:49954383540:8793516242242

This should be hard, I guess...
Hint

 It's not 7 numbers separated by :. The : in the code is for variable.

Solution

'N)){~}:KK{1#1md'NNf-Kc((K*}93*]'0f+34_2#t3_7#t

Python, 45
Code:
((((((()))))))+.1233445accehhiijlnnoprrrrsttv

Output:
0

Original

 print(eval((chr(43)+chr(45)).join(str(321))))

Cracked

Marbelous, 144
Code
______________________________++++++++++----......///0000000000000000111134477889::::::<<<<<<<<<<<=>>>>>>>>>>>@@@@@@AABLPTU\\\^^^^^^{{{{{{}}}}}}

_ represents a newline.
Output
2.718281828459045

I'll probably regret leaving in so many numbers..
JS Marbelous Interpreter
Unlike my other Marbelous cops, this one does not use cylindrical boards.

Brainfuck, 39
Code
++++++++++++++++++++------...<<>>>>[[]]

Output
SOS

Cracked.

CJam, 14 (Cracked)
Code
1.2e35 6.78e9%

Output
108183.05975155532

Cracked.

Insomnia, 14 (Cracked)
Code
(Only 1 space, as seen below)
yes|grep-99 ii

Output
101291340129

Interpreter

Cracked.

Python shell: 21 chars
A slightly beefed-up version of my previous attempt that I hope is harder to brute-force.
00112233445566778899^

Output (to shell):
15788895283

Cracked.

Python 2; 62 chars; Output: 100 chars; SAFE
Code:
    %%%''((((())))),-199;=[]___aaeeeeefggiiiillmnnnnooprrrstuv

Output:
1087654320987654316039744558401050205536516109500544976952359908183938933602037618678184519105773568

Solution:

 e='%ie%i';print long(sum([eval(e%(_,_-1))for _ in range(99)]))

QBasic, 37 bytes (Cracked)
Code:
PLAY "EN11E"
R = INT(11873105*RND)
?R

The code above (which includes two newlines) runs just fine: it plays a cute little tune and then outputs 8377039.* Only one problem...
Actual output:
 8946304

As always, output is followed by a single newline.
Original code:

PRINT 1801*5113 AND 1E7
R=LEN("RY?")

* Tested on QB64 Windows 7 desktop version. The pseudo-random RND should give the same result every time the program is run, unless seeded by RANDOMIZE. It's likely that the particular result will be different on different systems. But in any case (spoiler alert!)--the unscrambled program does not depend on RND. ;^)

Cracked.

Marbelous, 106
Code
_________________________!!0000011122223779999:::<<<<<<<<<<>>>>>>>>>>AAAbb\\\/MMNNOOOOOO+++++QQ{{{}}}}}}~~

_ represents a newline.
Output
3823160E090604030202

Hint

 Hexadecimal couplets.

This output should hopefully look familiar to you.
JS Marbelous Interpreter
This requires cylindrical boards (i.e. marbles pushed off of the board on the left reappear on the right and vice-versa).

ECMAScript, 90
Code
" "((((((()))))))+....;=FFFabcccdeeeffhhhiiiiiiilnnnnnnnnooooopprrrrsssttttttttttuuuuy{{}}

Output
function (){alert(this+"")}

@Sp3000 Nice work on the atob ones!

Cracked.

@user23013 Nice work!

@MartinBüttner amazing work on getting the exact solution.

Marbelous, 107
Marbelous is rather fun to program in.
Code
______________________!!***......000000000113444578:::::<<<<<=>>>>>>@@AAA\DDFF/////MM%%+++xxYYY{{{{{{}}}}}}

_ represents a newline.
Output
110000FFFFEEEEDDDDCCCCBBBBAAAA9999888877776666555544443333222211110000FFFFEEEEDDDDCCCCBBBBAAAA999988

JS Marbelous Interpreter
This requires cylindrical boards (i.e. marbles pushed off of the board on the left reappear on the right and vice-versa).

QBasic, 79 bytes (Cracked)
One more, just for kicks: the meta-PPCG edition!
Code:
"Louis, I think this is the beginning of a beautiful friendship."
- Rick Blaine

(Note the newline.)
Output:
Iodine

Cracked.

Python, 51 bytes (SAFE)
Code:
((((["tx*xx=2202022=xx*xt",prince:rinse+x*t]))));;;

Output:
86207823349459112201077150426144

Solution:

x=2*2*2+2;exec("x=int(str(x)[:],0x20);"*x);print(x)

Starting with x=10, interpret x as a number in base 32 and assign the result back to x. Repeat 10 times.

Works in both versions?

Just double checking - exactly one comma?

@MartinBüttner Yes, should work on any version (tested with 2.7 and 3.3).

@Sp3000 Exactly one. :)

Good old exec, the [:] did well to confuse.

Python, 55 chars [Cracked]
Works in both 2 and 3.
Code
((()))**+,.0112589:={}
____aacdefgiiimmmnnnoopprrrrsttu

Output
108723934648156901437468808002

Solution

 The intended solution makes use of the fact that __name__ == '__main__' for scripts as well as in the REPL.  More precisely, sum(map(ord,__name__)) == 801.

print(sum(map(ord,__name__))**10+1)
itforirngc={25.:89}

Cracked

JavaScript, 36
scrambled code:
trx=["bs","alie"];trx((x+x)guns(96))

output:
ion

Cracked.

Python 3, 21 [Cracked]
Code
pi.str.r42:():().[nt]

Output
pi

Cracked.

Java 8, 157 bytes.
Prints HELLO.
{ppt)i6s;ia.r eapxirf uw le([)i7{pt{7cdwo.,6aov viSjtrowbaor}avn6tS .imD,an}rtsia)eoerttt lt9((.eao[ut,E_tF9t7ge,e ejO.cbm}neiuiie7uiwFt2ri.ihc]no]cnys eanlc

Javascript - 10 (Cracked)
Scrambled Code
foeblast()

Output
W29iamVjdCBXaW5kb3dd

Answer

btoa(self)

Cracked.

Ruby, 65 chars.
code:
  #think(((((())))))*++---./;;==^^^eeeeeeiiiiiimpssttu{|||}112569

(it begins with two spaces)
output:
3
-7
-3
-3
-5
-4

(the output is separated by a new line)
This one shouldn't be too difficult.
Hint:

 This one relies heavily on bitwise operators, expecially or and xor

Hint 2:

 Some of the parentheses are optional, not really required and are used only to confuse the "Robbers".

PHP, 484 chars
s{9$_aer{cmnef]3o"{hmotee]e)=o(mdo/_o sf[di=_{yi(e]9i/lho_o${n}"lt!og]bnek"}[.ec$ [""kebe=-r7")}.0l} ]e]"oe "$3{]$c_)ln$[tee{u;r$cr "cln{e$du{$eodo+(eoc"]d$ocrcd]o e }0o}ll{oo)}no;{2tud;el#o.c $$0d dne{na[[ip2lcerihol dlH}+le [e [;l);[_"]d\.[]c$;n3d(]2$$:hitn"5d.i/tcepm["}noe "el[;;ex}Wx}}e"pe2o  d ,<m)t<tt;l{p$ih$ld$l \ cbye$ +1pi}[c]o l$c$ c"]$"(to}teue$d(]}l{[1e[d"}{)[e+ {e$$?il{">l nheb$)c$.ssbc\nusem;u$lpd=od)in {olsbnn{;}d76oy4sfc}}eicsd]i}xti$=f"ei{(o l$n(;hc :coce dats(ei

output:
hello world

Hint:

The code is NOT platform dependent (tested in os x and ubuntu), although it won't work in ideone or any other online IDE.

Hint 2:

 This code generates code in another language and executes it.

You realize this is code golf, right? The goal is to have a short program.

I wanted to do something challenging and difficult to "crack".

Python 2, size 13 (Cracked)
Code
ex00123679///

Output
0.0068493150684931503

Original Source

    6e1//073/0x92

Edited to make heading formatted

I used http://repl.it/

Cracked.

Python, size 30 [SAFE]
This one is just for fun, since my last one wasn't solved. :D
This one also has removed the workaround that squeamish ossifrage cleverly found. >:D
Still using http://repl.it/
Scrambled
:: rsin[~rot13(`0ddf`) + 69][]

Output
=> 'rot13'

Original Source

 str(d for d in[])[9:6:~0]+`13`
 I actually found this by accident. It creates a string of '<generator object <genexpr> at 0x221164>' (or some other address), then uses the rot at the end of generator and appends 13 to it.

Keg, length 7
Just for the fun of it.
5|(2&9)

Expected output:
2 5 2 2 2 2 2 2 2

 Since new cop solutions are disallowed, I will just leak the answer:

 5(9|&2)

Python [any] shell size 44 (Cracked)
4no_,2_[a(m] g]]fn_mie___e[nenr aa )1__[r3 _

Output
'a'

Cracked :-)

Java 6+ / Oracle implementation (Cracked by feersum)
Code (226 bytes)
There are 5 new line characters and 2 spaces. No other invisible/non-printable character presents.
"""  ((((((()))))))++,........
00000000000001122225677788
;;;DEIPPSSS[\\\\\\\]aaaaaaaaaaaabccccccccddeeeeeeeeeeeef
gggghiiiiiiiiiiiijllllmmmmnnnnnnnnnoooooopppppprrrrrrrr
sssssstttttttttttttttttttuuuuuuuuuuuuuvvxxyyyz
{{{{}}}}

Output
91 Unmatched closing ')'

The program has been tested to compile and run successfully on ideone, so please submit an answer with runnable demo there.

feersum's solution is far from my intended solution, so I will not reveal my intended solution since I'm going to modify it for a new challenge.

Is there anything wrong with this submission? By the way, Oracle's implementation should be the most common one around.

By "run successfully" does that mean it doesn't throw an error? (So you actually System.out.println("91 Unmatched closing ')')" or something along those lines)? Or is the output just output from println, errors, etc. combined?

@soktinpk: Output is to stdout.

Cracked

Befunge-93, size 17 (cracked)
Code
>_-,/""@
*#%+69pv

Output
@

Looks like it has probably used some non-standard feature of this interpreter.

Cracked, possibly

BBC BASIC, 187 - Cracked
Code
$$$$$$$$$$$$$$$$$$$$$((((((((((((((((((((()))))))))))))))))))))00000000111111111111111111111111122223333447778889999999CCCCCCCCCCCCCCCCCCCCCHHHHHHHHHHHHHHHHHHHHHINPRRRRRRRRRRRRRRRRRRRRRRT

Output
you'll never crack me

oh yes I will

PHP, 22 - Cracked by Martin Büttner
Code:
((()))*+..0117;cehinot

Output:
7

Original

 echo(int)((.1+.7)*10);

Cracked.

Bash shell script, 33 characters
Code
{int wk1}'caller$' hop|hop sewer

Output
shellpower

Cracked.

Haskell, 77
this poorly mixed code:
{tt))=Maprte((e)=))+-1%%&&tt} %%:i=ddeno:p:)illme((m;;;<=;()&&()):a6::1=(((no

output Should be
1
2
4
8
16
Code.exe: <<loop>>

Edit:
To clarify: the code should be saved in a file named Code.exe. otherwise the output would have the actual file name instead of Code.exe.
more than a week has passed since this was published.
original version:
main=mapM print(&);(&)=1:(&)%(&);(16:(:){})%t=t;(e:d)%(l:o)=(e+l):d%o;e<t=e-t

this uses a few tricks:

a variable named (&) that isn't a function

a record pattern not on a record (:){}

a useless definition of < to get people confused what to do with the extra = sign

the runtime prints <<loop>> because we entered into a trackable infinite loop (at the fifth element and on of (&)).

Regarding the last line, is it actually written to stdout?

@FireFly as an uncatched exception it is written to stdout and then the program terminates

When I checked locally, exceptions were printed to stderr for me (on linux), and not stdout.  I suppose it might print to stdout on windows, though?  Still seems a bit odd.

And you get a completely different message with jhc.

Python 3, 46
Program
""''''((()))*01==bbffiiillnnnooooppprrrrrttt

Plus two newlines.
Output
'(otlotb)'

Cracked

@feersum: invalid link.  Updated.

This one demonstrates something pretty neat (and surprisingly poorly known):
Python, 16
Code
""()7T\aeeelruvx

Output (from interpreter)
-2

I can't say much without giving a big hint, but this depends on an interpretation of the rules that I think is fair, reasonable, and expected.
I didn't make a separate answer for this next one since it bends the rules a little.  It's technically still fully compliant, but it's a little outside their spirit.  It's also really mean.  I'm sorry.
Python, 61 [SAFE-ish]
Code (plus two newlines)
#  ((()))*****----012345:aabbbcccdeeeggggginnoorsttuvvvyzzz

Output (from file)
635587791019258855467865682634760304773233019345006266045081668082247125111784951775232

Update: explanation:

 As guessed in the comments, this is indeed rot13 encoded.  The rules state "You are also not allowed to use hashing (or other cryptographic functions) in your program", but the character encoding defines how the editor interprets the bits that comprise the program, not the program itself.  Clearly, this violates the spirit of the rule.  Original source:
 #--coding:rot13--
 sebz zngu vzcbeg*
 cevag(vag(ybt(5)**420))

Is the second one using ROT13 encoding? Because, if so, yes that is pretty mean. :P

(Also if so you might want to specify that it's Python 2, not 3. Ignore me if I'm wrong though.)

The question forbids "cryptographic functions". ROT-13 is technically a cryptographic function, so it would be forbidden.

By output from "interpreter", do you mean that it must me entered in the REPL? If so it isn't valid as a stand-alone program is required.

I've cracked the first one, assuming Python 2 is acceptable.

@feersum: where does it say stand-alone?  Also, character encodings are not part of the program itself.

@imallett The question asks for a program. It's standard rules for the site that a program means a program, and not some code fragment which could be evaluated. And a cryptographic function is a cryptographic function regardless of how it is invoked.

Bash
23 characters long.
Cracked by user23013 [link].
BASH_VERSION is "3.2.53(1)-release"
Source (original)

 _(){ q=echo;$q "$q";};_

Source (scrambled)
;{e) $ qq"}";oh_$_=q(;c

Output
echo

I believe there should be one more space character.

But it is still possible without that. Cracked.

JavaScript, 285
Code
\n\n\n\n\n\n      """"""(((((((()))))))),,,,.........///////0001111222222333334566666777777889999:========ACCEGHJLLLMNORSTTX[]_aaaaaaaaaaaaaaaaaabbbccddddeeeeeeeeeeeeeeeeeefffffgghhhhhiiiiiiiiijlmmmmmnnnnnnnnnoooooooooooooooopppppqrrrrrrrrrrrrrrrrrrssssssssssssssstttttttttttttttuuuvvvwwwwxz

Note: The \ns are one character.
Output
AZ

Please refrain from revising your post after posting, especially in a challenge like this.

Cracked? http://codegolf.stackexchange.com/a/41239/32372

Python, 41 bytes
Code:
_dtrupar_p)o_(prm(txnrr_e)i)(mei er,(.)ps

Output:
6314

Cracked... and -1 for being implementation-dependent :P

C (gcc) - 43 - Cracked
Code
""%%&(()),7;[]aabdeeefiiiimnnnnpprrsstuux{}

Output
se7en

Trust me, you don't want to open this box...
(My unscrambled code will only work in non-strict C. For example, here)

Original

 main(superbia){printf(&unix["%se%den"],7);}

Is it permitted to output a newline after se7en?

Cracked.

unix is an undeclared identifier for me.

@feersum Yeah, I don't think this would've counted then, even if nneonneo hadn't cracked it. I thought that unix was still defined if your OS was unix based, but I guess I was wrong ;_;

And if your OS isn't unix-based?

@feersum ... yeah I should've put that in the answer... Sorry, I don't know what I was thinking...

Arithmetic (ECMAScript, Java, C, C++, BASIC, Perl, Python, Ruby), 31
Code
((((((()))))))****++++111122222

Output
77

Cracked.

Nice work both of you!

PHP, 54, Cracked
Code
$$$$$$$$$$&(())11122;;;;<<====^^aaaabbbbbbceehhilow{}

Output
42

Original

 $a=21;$b=21;while($b){$a^=$b;$b=($b&$a^$b)<<1;}echo$a;

Original idea

Cracked.

Haskell, size 34 (Cracked)
Shuffled:
pfdi0xf7(anI5i7r1):^b3nf=2x:t2tm0n

Output:
-1121766947

I'm tempted to claim that this violates the "you may not use cryptographic functions" rule, except that any self-respecting cryptographic function would use a big prime instead of 2^64 for its modulus... Perhaps if I knew a bit more I would know how to exploit this choice. Very clever choice of problem.

cracked

@DanielWagner Good job. I'd say that exponentiation isn't a cryptographic function, even with the 2^32 modulus. Perhaps I should have used ** instead of ^ to make the guess slightly harder.

Number Theory != Cryptography

Python 2 - 57 Cracked
Code
''((()))+++++++,,,,.000000001111113444589abchiijmnnopprrt

Output
blue

Blue is the best colour ;)

Cracked

ECMAScript, 25 (Cracked)
Executed on window object
Code
applet.stellar[flyer,(a)]

Output
function alert() { [native code] }

Just double checking, are you sure, you're not missing a comma? (Alternatively, does it produce errors as a side effect?)

The built-in function alert isn't mentioned in the ECMAScript spec, so I think you need to be more specific about the execution environment in which this output is produced.

There are 24 characters given in your answer

@MartinBüttner correct. Thank you for that. Adding comma.

@PeterTaylor Good point. I'll put "executed on window object", if that's cool with you?

@es1024, yep that's correct. Thank you for that. Adding the extra character.

Cracked.

@MartinBüttner Nice work!

I don't think the window object is part of the ECMAScript spec either. What compiler or interpreter are you using?

PHP, 27 (Cracked by bwoebi)
Code:
$$((()))02679;;=__bdeehiinx

Output (default on PHP 5.4.x):
3.1415926535898

Output (default on PHP 5.5.x):
3.14159265359

Hint: It depends on your php.ini precision, so hopefully it's acceptable.

Original:

 $_=hex2bin(7069);die($_());

Cracked ... hey, please make the next one a challenge, not cracked in 5 minutes; please :-)

C, 28 (cracked by feersum)
0124689aimnpsssstu=;;&{}(())

Prints Hi!

Cracked

Drat, you beat me to it

Oh come on ! 7 minutes ? You are awesomes guys.

Java, size 108
Code
forprintmymostfaultSent66{{{}}}.......;""(((())))%,*++//\\--''''''''''''main static class void public String

Output
3.141593

Cracked

Python, size 37
Scrambled:
"    "*+++.123334:=
=deefiinnoprrstuu

Output:
12369.0

Cracked

PHP, 62 chars
"fine".Music <= radio?'==;;'(.')()+')+$yeTi:2('3(;)1$$$hoo.'.

Output:
1. Monday 2. Tuesday

Cracked

Python 2, 80
Source (original)

 "no %, *, any for loops, nor pow()"
 print int(str((61**38)/(702+4)+5)[9:])

Source (scrambled)
"         "%
((((()))))
***++,,,/
0123456789
:>[]afiilnnnnnoooooo
ppprrrrsstttwy

Output
28557152413644043173796536772347528819922074855728983445

Python 2, 45 [safe]
Code:
3
((([])))**``,,::-=>ccddeeiinoopprrttuuuuuuw

(Contains one newline and no further whitespace.)
Output:
67156035937662544426

Hint (though I'm not sure it helps):

 If you replace the 3 by a 4 the output grows to 993 digits. For 5 it's even 91585 digits.

Solution:

u=3
print`reduce(pow,(u*u-(oct>id),)*u)`[::u]

Explanation:

Okay, maybe this was overdone. :-)
The (oct>id) was a red herring and is just a fancy way of spelling 1 because in Python functions are ordered alphabetically by name. Using tuple multiplication, the argument of the reduce function then boils to reduce(pow,(8,8,8)) which is ((8)**8)**8 or6277101735386680763835789423207666416102355444464034512896. Because this would be an easily recognizable number, it's then converted to a string and only every third digit is printed.

C++, 244 bytes (one linebreak, 19 spaces) (Cracked)
Source
 !#%''''''''''''''''''''''''((()))++,,,,,,,,,,,/00122224::;;;;;<<<<====>CCCCCCDDDDDD[[]]aaaaaaaaacccdddeeeffhhiiiiiillllllllllmmnnnnnnnnnnnnnnnnooooooooooooooooorrrrrrrrrrrrsssstttttttttttttttttttuuuuuuuuuuuuuuwwwwwww{{{{}}}}

Output
hello world!
A couple hints

Output is achieved using a really unorthodox process.
The source code isn't 'scrambled', per se. (Just alphabetized.)

How many spaces? I counted only 224 non-whitespace characters. With the initial space and new line, that makes 226 bytes, not 244.

Cracked, I think

I had a method in my scrambler that counted the number of bytes that were in the file it loaded into memory. It said '244 bites', so I went with that. (Edit: verified character count with an ascii counter online. 244 is accurate.) Also, @squeamishossifrage, It does the same thing, but the extra characters ARE used, not just tossed into the end. =P

I just realized most of those characters are used in variable names. Didn't realize smallest score won. >_<

Perl, 53 bytes
Code:
$thriller='24'&&$prng=4;tar xvw'~'.$e/=3332+42*$i/~$r

Output:
3155242264414961265415109674813320

No trailing newline this time. Tested in Perl 5.18.2, but should work fine on other versions.

Marbelous, 48 (Cracked)
Code
_______&&--...../000000000011111111:<<=@@@@\{}}}

_ represents a newline.
Output
"

(Yes, just one double quote.)
JS Marbelous Interpreter
Unlike many of my other Marbelous cops, this one does not use cylindrical boards.

Cracked.

J 25
+3oh.5- #+-ii#3c!//4e.2%/

output
3

Cracked.

Marbelous, 144
Code
______________________________!!!&&+++++----..........////////0000000000000000000000111111227888::::::<<<<<<<<<=>>>>>>>>>@@@@@@AAOO\\\\^^^{}}}}}

_ represents a newline.
Output
31 2F 2E 2C 2B 29 28 26 25 23 22 20 1F 1D 1C 1A 19 17 16 14 13 11 10 0E 0D 0B 0A 08 07 05 04 02 01

There is a space+newline at the end.
JS Marbelous Interpreter
Cylindrical boards required.
Hints:

 A001651 in hexadecimal, backwards

 (a >> 4) and (a << 4) >> 4

C - size 62 (Cracked)
Code:
)#<("pitiful tit,handfin descended in +18_minor.")>#(%{;__*}

There are 4 spaces and 2 newlines \n in the source (not in output).
Output:
17

Possible error thrown not taken into account.

Would you please confirm the cracking attempt by user23013? The cracking attempt seems to have too many spaces.

@n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳ wasn't gonna until I got home, but looking at it quickly I'd say there's 5 spaces in his attempt. Only 4 spaces in the actual code, though, so doesn't pass.

@user23013 Sorry but 1 space too much

Cracked.

C - size 19
Code:
int main(){return;}

There is 1 space.
Output:
Segmentation fault

or similar.
Compiled in http://codepad.org/

OS? Compiler? Segmentation fault usually is the by product of undefined behavior, and it varies between systems.

@n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳ edited

Cracked.

Javascript (41 bytes) - Cracked
It should be a piece of cake to crack.
Here is the code:
'cccefhiinnnnooorrrrsstttttuuu)))} {(((.'

This is supposed to give the window object.
Probably will work on node.js
Have fun!
P.S.: Please don't crack it!!!

Sorry, cracked.

@MartinBüttner Try to crack this one: http://codegolf.stackexchange.com/a/41299/14732

C, 63 (Cracked)
Code
int main(_){_;_<_<_;_=_;_______;printf("%d",_<=_<<_||_<<_<=_);}

Output
131088

Original Solution

__;int main(_){__=_<<_<<_;__=_<<__;_<<=__|_;printf("%d",_|__);}

Cracked

Javascript (82 bytes) - Cracked
Since my first Javascript attempt was cracked in 6 hours, I decided to make another one!
Here it is:
eval('zov=~-1+(ii=1<2);if(0^1<2 in[3]<=+[])ii+[zov]+[]<<ii;//cog=lovr;s.n,r,o.j');

As the PHP answer, you can run it and it will return 0.
The unscrambled version outputs this:
131713115131713131131713115131713163131713115131713131131713115131713112713171311513171313113171386

I hope that this one survives a day.
Have fun and don't crack it!!!

Cracked.

Python 2, 37
Code
print(len(ord(Emvies.priwilimmstys)))
Output:
1

Cracked

PHP (80 bytes) - Cracked
Yes, this is one more answer from me!
Here is a new one, fresh for you all:
$$__=aAaAaa;$$___=(b^C^Fff^IIi);$$____=j^k^N^Oo^PPp;$$_____=Qrr+tTT.(UWW<XXyZ);;

As always: You can run it and it will print absolutely nothing. (same as the numeric value 0 converted to string)
The output:
:

That's right, 1 byte of output!
Go ahead and have fun with this one!

Cracked.

Python, 90 bytes (SAFE)
Kinda long, but I enjoyed putting this together.
Code:
??(((())))+++++++,1111111111111111111111:;;<<<<======>>>>>[[]]ehiilnnnnnnnnnnpppprrrsstttw

The ?s represent two newlines.
Output:
6167185029251277541387741632208161040852042602130139041952976

Output is followed by a newline. Works in Python 2 or 3.
Solution:

n=11111+1111+111+1;p=str()
while n>1111:n=[(n<<1)+n+1,n>>1][n>>1<<1==n];p+=str(n)
print(p)

Calculates several iterations of the 3n+1 function starting at 12334 and continuing until the value dips below 1111, concatenating the results together. For obfuscation, uses only 1's and bitwise operators to calculate the function (which would more straightforwardly be n/2 if n%2==0 else 3*n+1).

PHP (46 bytes) - Cracked:
Yet another one from me.
This one is kinda easy.
I did my best to have 1 and only 1 solution.
Here it is:
echo$o=rand(m^z&E+$i,$i=(H<Y)or$Y[$i+f<<z]);;;

And outputs:
band

As with some of my previous answers:

PHP (46 bytes)
Javascript (82 bytes)
PHP (80 bytes)

You can run the scrambled code.
Depending on it's mood, outputs either 0 or 1.
Have fun!

Cracked.

PHP (33 bytes) - Cracked:
This one is pretty easy to crack.
It only works on linux.
Scrambled code:
X1dFu7Te48oklB ^ HDecnX0iTch0T6g;

Output (if everything goes right):
1

PHP (24 bytes): (I won't count this one, untested)
This is the windows-only variation of the SAME code.
The difference is the size and that I needed to add quotes.
Scrambled:
'dc6iunXB7 ^ heoedcX4l';

Output:
1

Both scrambled codes can be run.
Have fun!!!

Cracked.

Bash 4.2.47(1) on Linux, 47 characters
${porcel-=str('pix fep\n     pp/pp/'); fec1/; }

Output, without newline:
pp

Finding some solution is easy:
printf pp;o='${cel-sr(xe\     pp/pp/) fec1/; }'

Try to find the original code, without comment-like things like thow-away assignments or "hungry" identifier names.

That's not how this challenge works though. ;) if you want people to find your original code, it's your job as a cop to make sure no other solution exists.

Cracked...it was very kind of you to post the solution!

C - size 33 (Cracked)
Code:
#() {} * +257;
adeeefiimnnnppprrtu

So 3 spaces and 1 newline
Output:
Exits with return code 173

Cracked

Javascript, 35
Scrambled: a)o29t;((1lae1.2(ll=h3t(;rM)4)g)lll7
Output: 0.674284933420515

Cracked

JavaScript, 72 [SAFE]
Output:
35616001553385

Code scramble:
Math.exp(unoat(exp){ecit((("x")ps.in(1.19+21)).sit())+flr()})loop[ferln]

Unscrambled:

(function(exp){alert((""+exp.sin(1.21)).split(9)[1])+exp.floor()})(Math)

Python, 39 [Cracked]
Scrambled code
for{{5210},{101},{6}}at{print(("m.",))}

Output
06555

Cracked yesterday but forgot to post here, sorry.

Processing, 77
Scrambled code -
// L0L =>
line(987654321);
Lint( <.< ^=^ ;=; >=< ^ );
script {wh LLL >> LLL};

Prints this to the console -
11677374506454972755473030033

It also opens a small window with a grey square in it, the same thing that shows up when you run a totally blank sketch. I don't think there's anything I can do about this in Processing.
Tested in Processing 2.2.1 but should work in pretty much any version. Thanks for playing!

Javascript - 68 [SAFE]
Scrambled Code
''''((( )))++,,.00012567;==ABCCISaaadeeffffghimnnooprrrrrssssssttvxx

Output
9+10

Answer

var s=String,sf=s.fromCharCode;sf(57)+sf('0x2B')+parseInt('0x0A',16)

Javascript - 15 (Cracked)
Scrambled Code
''O1ahintsM.()+

Output
0.8414709848078965O

EZ PZ :D
Answer

 Math.sin(1)+'O'

Cracked.

Python, 13 [Cracked]
Code
printline("")

Output
6

Cracked.

PHP, 56 chars
  ""$$((())),.0;<=>??EFIL[\]______herecefhillnnoopppstw2

(begins with two spaces)
Output

3249

EDIT:
I thought this one was fairly easy.
Hint:

 This code relies on just one math function.

Python 2 (Cracked)
Scrambled Code:
int r*37230,
p rp tin * 73

Output:
222222

Cracked.

Python 2, 78
int pint=2222222****************2222222****************2222222,
rp r= 61727176

Output
16777216

UPDATE
The output has a newline after it.

Actually, the output had a newline after it.

Anyway, my solution has a trailing new line after all.

Plus, you gave the wrong url.

OK, here is the correct URL. Cracked (No change to the source code, the output should still be valid).

Cracked.

Python, size 30 (Cracked)
This one is just for fun, since my last one wasn't solved. :D
Again using http://repl.it/
Scrambled
:: rsin[~rot13('0ddf') + 69][]

Output
=> 'rot13'

Original Source
Will be posted later, because I didn't like his workaround. Solve THIS instead.
Nobody solved it! Muahahaha!

 str(d for d in[])[9:6:~0]+'13'
For an explanation, go to the link above.                    ^

Cracked

It appears you found a workaround. Editing it to remove the possibility of that workaround.

Python, size 15 (Cracked)
This one is for the gold, though I find that unlikely.
Again using http://repl.it/
Scrambled
[~]/:.*034`57:`

Output
=> '6991'

Original Source

 `.03*7/5`[::~4]
~4 is just a fancy way to write -3

Cracked

Does anyone know how I can correctly format the code in the solution? The backticks need to be escaped, but it'd be nice if the code could be formatted like code also (which normally involves surrounded with backticks, but it won't work.) Indenting with 4 spaces isn't working either.

@squeamishossifrage Thanks.

CMD, 9 (Cracked)
/0at!es!!

No spaces in source - Just a big fan of Oaties.
Output: 1

Cracked

JavaScript, 24 characters
Code:
('oogles').oil + 'chn';

Output:
hi

(with newline)
Works on pretty much any browser, or Node.js (but not Rhino).
Should be very easy to crack.

Cracked.

Sorry, there was an extra period in the scrambled version. Your solution works, though!

CMD, 21 (Cracked)
echo "/test!!">>afile

No files are produced.
Output: 0
Original program
set /a"!echo>>!tfile"

I evaluate two separate strings with ! (negation), each producing 1 - then perform a logical shift >> on the two values - which produces 0.

Cracked

Javascript (Node.js REPL), 11 bytes
Just for fun. Here is the verifier for the program that generates a circular list.
([x[0]==x])

Expected output:
[ [Circular] ]

Spoiler (don't cheat!)

 Spoiler since no cop solutions are allowed anymore (written by wizzwizz4):
 (x=[])[0]=x

05AB1E, 7 bytes (Cracked by Bubbler)
Quite obvious if you examine the output, right?
BA5E10™

Expected output
Abcdefghijklmnopqrstuvwxyz

Cracked.

Actually, 6 bytes (Cracked by Bubbler)
Hello!

Expected
485165195.4097903

Cracked.

C, 117 bytes
Output:
*old meats*

Scrambled eggs:
o]00a;ci&955t[]e,o}ps,;5a(;o1-e=drffe0(px2,m*7^100ni,c=,,40o4xp;xom170&),at{9)x9=]h={p-,o5cm[;(nd4ex,,r([7r},xc)4)7,,

You earn my respect if you can guess how this program was scrambled.

Python 3, 124 bytes
ticdinstliub________.:1()niprt prinont"if"
ssA sslacpa:
()Aa=
"prprontint"".a
""a()intpr:________.insbuilticd.  nipront. aif

Try it online!
Should output a.

Python 2, 89 - Cracked
Code
   ''''''''((()))*,,,,...12;;=BFGGIIIILPRaaaaaabceeeeeeffgggggiiiiiklmmmmmmnnoopprrrsttvw

Output
No output to STDOUT ;)

Cracked. Turns out no unscrambling was necessary!

@feersum I don't know if it's allowed, but I clarified what my code should do...

"Your program and output must use printable ASCII." And no fair adding new output after I already cracked it...

Java 6+ / Oracle's implementation (218 bytes)
Code
 ((((((()))))))*+,...........
000000000111222225677;;;
DEIPPSSS\\\\\\aaaaaaaaaaaabccccccccddeeeeeeeeeeeeffggggh
iiiiiiiiiiiijjllllmmmmnnnnnnnnnooooooppppppqqqq
rrrrrrrrssssstttttttttttttttttttuuuuuuuuvvxxxxyyy
{{{{}}}}

There are 5 new lines and 1 space. No other invisible character.
Output
723Unmatched closing ')'

With these many characters, it is probably open for many possibilities.
Hint
I don't know if there is any other solution, but it seems I have limit the solution to the following direction quite well.
import
java.util.regex.*;
class{public
static
void
main(String){try{Pattern.compile(((()))+.....000000000111222225677DI\\\\\\aaacdeeeeeffggiijnnopqqqqrstttuuuuux,);}catch(PatternSyntaxException ){System.out.print();}}}

And second hint is long-standing bug.

Hmm, seems familiar, didn't I already do that one?

@feersum: Yes, it is a rehashed version, but slightly modified - not sure if it can be solved similarly, though.

Python - 62
Code
odado96\n5oar)mamn0arrd)(snp,nn.2m7dtitit.\nrmr)3i4(n nrope81(ed

Output
60132

Answer:

 import random
random.seed(6)
print (random.randint(9805,73241))

Does this work in both Python 2 or 3?

Not sure since I don't have Python 3.
Probably it does.

Really, even with the argument of print needing parentheses?

Well, in this case it will be missing those parentheses.

Also, are there any newlines? While we're at it :)

Now for the third time it has a different set of characters and a different output.

I had to change a few things that changed the output. Sorry for the inconvenience. Now it's working fine.

Do the \ns represent newlines or a \\ and an n ?

\n are newlines

In that case the character count is not equal to the number of characters given.

cracked gg

I had a bad feeling that the first line was import random...

Yes, random seem counterintuitive in search for a specific output, but since seed() makes this less random, it's still valid.

@f.rodrigues One could argue, that using a seed and randomint counts as hashing.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/

authors: n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳

authors: Алёна Дворецкая

authors: Ариунзаяа Отгонжаргал

authors: Максим Виноградов

authors: Роман Качура

authors: ابو رغد المنهالي

authors: فریبا کشیده گرگیج

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

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