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International Obfuscated C Code Contest Winners

182 points by lelf 14y ago

16s 14y ago
deckmyn.c is my favorite. That's beautiful source code. Edit: This one is fun to look at too: http://www.ioccc.org/2012/hamano/hamano.c http://www.ioccc.org/2012/hamano/hamano.c
- makomk 14y ago
  hou.c is kind of neat too. Looks like a big blob, but actually forms an image via cunning use of syntax highlighting.
  - rlt3 14y ago
    Is it supposed to be Kyubey? I pulled it up in vim, but the syntax highlighting didn't expose anything for me.
    - Tobu 14y ago
      It is. Though it only works well if you use it like this: ./hou ansi.txt hou.c
      - deleted 14y ago
        [deleted]
biot 14y ago
Tromp's entry is amazing. Source: http://www.ioccc.org/2012/tromp/tromp.c http://www.ioccc.org/2012/tromp/tromp.c Spoiler: http://www.ioccc.org/2012/tromp/hint.html http://www.ioccc.org/2012/tromp/hint.html It's based on a minimal implementation of Binary Lambda Calculus: http://en.wikipedia.org/wiki/Binary_lambda_calculus http://en.wikipedia.org/wiki/Binary_lambda_calculus
- batgaijin 14y ago
  Did he invent Binary Lambda Calculus as well?!?
  - jlgreco 14y ago
    "Binary lambda calculus is a new idea introduced by John Tromp in 2008" Apparently so. Wow.
  - jrajav 14y ago
    He actually first mentioned the idea as early as 2004: http://web.archive.org/web/20040602202609/http://homepages.cwi.nl/~tromp/cl/cl.html http://web.archive.org/web/20040602202609/http://homepages.c...
- wamatt 14y ago
  >Tromp's entry is amazing. It really is, which leads me to wonder how difficult it would be, to deobfuscate this into code that can be understood by the average programmer? At least in terms of being able to say what it does, without being told. While most would probably regard security through obscurity as bad practice, perhaps there are practical uses in certain contexts.
  - gizmo686 14y ago
    When you are talking about mid to high level security, you assume that your adversary is not an average programmer, but rather a train security analasyst. A major part of that field is looking finding vulnurabilities in machine code. Based on the statement "Obfuscation is due entirely to conciseness" in the author's hint, it sound like he did not use any techniques that would have a significant effect on the generated machine code.
  - astangl 14y ago
    John asked me to review his entry prior to submission, and we had some ongoing discussion as he worked through his revisions. He initially pointed me to a "minimally obfuscated" version to analyze. I'd say it took me a good hour or so to feel like I had a pretty good understanding of its workings, and even then I still wasn't clear on some details of the I/O model and a couple other things. Most of the evolution from that point was finding ways to reduce the code size, then finally reformatting into a lambda. I credit John for not succumbing to gratuitous obfuscation, nor gratuitous use of macros to shave bytes. I suggested to him at one point to consider reducing the entire program to a single loop. He didn't think it would be shorter and pointed out that he had made a similar transformation in an earlier IOCCC entry of his, his infamous maze program, so I believed him and didn't go through the effort to verify for myself.
kqr2 14y ago
There's actually a book that covers some of the old contest winners: Obfuscated C And Other Mysteries by Don Libes http://www.amazon.com/Obfuscated-Other-Mysteries-Don-Libes/dp/0471578053/ http://www.amazon.com/Obfuscated-Other-Mysteries-Don-Libes/d...
- mtoddh 14y ago
  +1 for this book - I rarely see it mentioned when it comes to C books. Reminds me of van der Linden's C book in that it uses non-traditional examples to illustrate concepts.
- johnx123-up 14y ago
  My all time favorite is Wesley's code in 1992 that prints world map (found through A to Z of C): main(l ,a,n,d)char**a;{ for(d=atoi(a[1])/10*80- atoi(a[2])/5-596;n="@NKA\ CLCCGZAAQBEAADAFaISADJABBA^\ SNLGAQABDAXIMBAACTBATAHDBAN\ ZcEMMCCCCAAhEIJFAEAAABAfHJE\ TBdFLDAANEfDNBPHdBcBBBEA_AL\ H E L L O, W O R L D! " [l++-3];)for(;n-->64;) putchar(!d+++33^ l&1);}
  - pooriaazimi 14y ago
    Care to share the output also (for those who don't have a C compiler handy)? Thanks!
    - johnx123-up 14y ago
      Screenshot mentioned there too.. in 2nd page http://guideme.itgo.com/atozofc/ch13.pdf http://guideme.itgo.com/atozofc/ch13.pdf
    - zer 14y ago
      https://gist.github.com/3910435 https://gist.github.com/3910435
ioccc 14y ago
We hope you enjoy the 21st IOCCC results - we enjoyed judging the entries. If you have any feedback on the competition for the Judges, please contact us using the details at http://www.ioccc.org/contact.html http://www.ioccc.org/contact.html Thanks. SimonC.
- wtracy 14y ago
  Just curious, since you're handy to ask: How do the judges view code that depends on external (but cross-platform and FOSS) libraries? Only Xlib is specifically mentioned in the rules. I'm specifically thinking of libpng, but I'm sure one could think of other meaningful examples.
  - dlowe 14y ago
    I don't know the official policy, but anecdotally, I won with an entry that used libperl back in 2000: http://www.ioccc.org/years.html#2000_dlowe http://www.ioccc.org/years.html#2000_dlowe
    - wtracy 14y ago
      The fact that it won for "worst abuse of the rules" doesn't help your point much. :-)
    - Natsu 14y ago
      I love this bit of history from the hint :) Aside: history... Larry Wall wrote the original Perl in 1986-87, the same two successive years he won the IOCCC. I hope this program helps you to realize that this was no fluke - that Perl and Obfuscation are as inseparable as, say, camels and humps.
  - ioccc 14y ago
    Generally we don't like lots of external dependencies. External libraries do change over time - would such an entry work 10 years from now? The judges do use and test the entries using different operating systems. What will operating systems look like in 10 years? Having said that :-), if the entry has merit on its own and not just because of the external dependency, then it might "win".
dlowe 14y ago
FWIW, if anyone is curious to see the process of building my entry ("Conway's game of death") I just made the repo public: https://github.com/dlowe/death https://github.com/dlowe/death This contest is great. I'm so glad it's happening regularly again :)
- MTGandP 14y ago
  A lot of your commit messages don't make any sense. Is there any point at which the program was fully functional but non-obfuscated?
  - dlowe 14y ago
    More-or-less yes. I started compressing and obfuscating the code after https://github.com/dlowe/death/blob/7fcbcabb9f69bf0cdfff4651c9a2b8d976898cbf/death.c https://github.com/dlowe/death/blob/7fcbcabb9f69bf0cdfff4651... Sorry about the commit messages. Think of them as part of the obfuscation ;)
- lifthrasiir 14y ago
  I've also posted the history (or, "scratchpad") of my winning code (2012/kang) to Gist: https://gist.github.com/3909337 https://gist.github.com/3909337 (possible spoilers ahead) Okay, it is quite cryptic and a bit unorganized (as I frantically updated the code as I saw any optimization opportunity), but it may be interesting to see how the code is gradually shorten.
- omoikane 14y ago
  Process of building my entry is mostly in spoiler.html.gz. For your viewing convenience, it's also here: http://uguu-archive.appspot.com/nyaruko/edit.html http://uguu-archive.appspot.com/nyaruko/edit.html
  - dlowe 14y ago
    How did you record that?
saint-loup 14y ago
Fun fact: David Madore, co-author of the conspiratorial contest, actually didn't mean to obfuscate his code. The winner page: http://www.ioccc.org/2012/grothe/hint.html http://www.ioccc.org/2012/grothe/hint.html The source in french: http://www.madore.org/~david/weblog/2012-10.html#d.2012-10-14.2083 http://www.madore.org/~david/weblog/2012-10.html#d.2012-10-1...
customary 14y ago
I must admit I was disappointed in last year's contest winners, namely their general focus. I thought maybe something had been lost in the years the contest was not running. But these entries are great! Binary lambda calculus? Top notch. IOCCC is back! Check this out { echo one;echo two;echo tres;}|./kang result: the sum in hex
ewanmcteagle 14y ago
Seems to be the same John Tromp of the Computer Go bet. http://dcook.org/gobet/ http://dcook.org/gobet/
- Evbn 14y ago
  Wow, John accurately predicted the year computer Go would beat him, 15 years in advance, and made a $1000 by being slightly conservative. Nice long bet!
venomsnake 14y ago
Amazing entries. These are also the winners for "language you currently hate" clear code contest.

182 points by lelf 14y ago

16s 14y ago

deckmyn.c is my favorite. That's beautiful source code. Edit: This one is fun to look at too: http://www.ioccc.org/2012/hamano/hamano.c http://www.ioccc.org/2012/hamano/hamano.c

makomk 14y ago
hou.c is kind of neat too. Looks like a big blob, but actually forms an image via cunning use of syntax highlighting.
- rlt3 14y ago
  Is it supposed to be Kyubey? I pulled it up in vim, but the syntax highlighting didn't expose anything for me.
  - Tobu 14y ago
    It is. Though it only works well if you use it like this: ./hou ansi.txt hou.c
    - deleted 14y ago
      [deleted]

biot 14y ago

Tromp's entry is amazing. Source: http://www.ioccc.org/2012/tromp/tromp.c http://www.ioccc.org/2012/tromp/tromp.c Spoiler: http://www.ioccc.org/2012/tromp/hint.html http://www.ioccc.org/2012/tromp/hint.html It's based on a minimal implementation of Binary Lambda Calculus: http://en.wikipedia.org/wiki/Binary_lambda_calculus http://en.wikipedia.org/wiki/Binary_lambda_calculus

batgaijin 14y ago
Did he invent Binary Lambda Calculus as well?!?
- jlgreco 14y ago
  "Binary lambda calculus is a new idea introduced by John Tromp in 2008" Apparently so. Wow.
- jrajav 14y ago
  He actually first mentioned the idea as early as 2004: http://web.archive.org/web/20040602202609/http://homepages.cwi.nl/~tromp/cl/cl.html http://web.archive.org/web/20040602202609/http://homepages.c...
wamatt 14y ago
>Tromp's entry is amazing. It really is, which leads me to wonder how difficult it would be, to deobfuscate this into code that can be understood by the average programmer? At least in terms of being able to say what it does, without being told. While most would probably regard security through obscurity as bad practice, perhaps there are practical uses in certain contexts.
- gizmo686 14y ago
  When you are talking about mid to high level security, you assume that your adversary is not an average programmer, but rather a train security analasyst. A major part of that field is looking finding vulnurabilities in machine code. Based on the statement "Obfuscation is due entirely to conciseness" in the author's hint, it sound like he did not use any techniques that would have a significant effect on the generated machine code.
- astangl 14y ago
  John asked me to review his entry prior to submission, and we had some ongoing discussion as he worked through his revisions. He initially pointed me to a "minimally obfuscated" version to analyze. I'd say it took me a good hour or so to feel like I had a pretty good understanding of its workings, and even then I still wasn't clear on some details of the I/O model and a couple other things. Most of the evolution from that point was finding ways to reduce the code size, then finally reformatting into a lambda. I credit John for not succumbing to gratuitous obfuscation, nor gratuitous use of macros to shave bytes. I suggested to him at one point to consider reducing the entire program to a single loop. He didn't think it would be shorter and pointed out that he had made a similar transformation in an earlier IOCCC entry of his, his infamous maze program, so I believed him and didn't go through the effort to verify for myself.

kqr2 14y ago

There's actually a book that covers some of the old contest winners: Obfuscated C And Other Mysteries by Don Libes http://www.amazon.com/Obfuscated-Other-Mysteries-Don-Libes/dp/0471578053/ http://www.amazon.com/Obfuscated-Other-Mysteries-Don-Libes/d...

mtoddh 14y ago
+1 for this book - I rarely see it mentioned when it comes to C books. Reminds me of van der Linden's C book in that it uses non-traditional examples to illustrate concepts.
johnx123-up 14y ago
My all time favorite is Wesley's code in 1992 that prints world map (found through A to Z of C): main(l ,a,n,d)char**a;{ for(d=atoi(a[1])/10*80- atoi(a[2])/5-596;n="@NKA\ CLCCGZAAQBEAADAFaISADJABBA^\ SNLGAQABDAXIMBAACTBATAHDBAN\ ZcEMMCCCCAAhEIJFAEAAABAfHJE\ TBdFLDAANEfDNBPHdBcBBBEA_AL\ H E L L O, W O R L D! " [l++-3];)for(;n-->64;) putchar(!d+++33^ l&1);}
- pooriaazimi 14y ago
  Care to share the output also (for those who don't have a C compiler handy)? Thanks!
  - johnx123-up 14y ago
    Screenshot mentioned there too.. in 2nd page http://guideme.itgo.com/atozofc/ch13.pdf http://guideme.itgo.com/atozofc/ch13.pdf
  - zer 14y ago
    https://gist.github.com/3910435 https://gist.github.com/3910435

ioccc 14y ago

We hope you enjoy the 21st IOCCC results - we enjoyed judging the entries. If you have any feedback on the competition for the Judges, please contact us using the details at http://www.ioccc.org/contact.html http://www.ioccc.org/contact.html Thanks. SimonC.

wtracy 14y ago
Just curious, since you're handy to ask: How do the judges view code that depends on external (but cross-platform and FOSS) libraries? Only Xlib is specifically mentioned in the rules. I'm specifically thinking of libpng, but I'm sure one could think of other meaningful examples.
- dlowe 14y ago
  I don't know the official policy, but anecdotally, I won with an entry that used libperl back in 2000: http://www.ioccc.org/years.html#2000_dlowe http://www.ioccc.org/years.html#2000_dlowe
  - wtracy 14y ago
    The fact that it won for "worst abuse of the rules" doesn't help your point much. :-)
  - Natsu 14y ago
    I love this bit of history from the hint :) Aside: history... Larry Wall wrote the original Perl in 1986-87, the same two successive years he won the IOCCC. I hope this program helps you to realize that this was no fluke - that Perl and Obfuscation are as inseparable as, say, camels and humps.
- ioccc 14y ago
  Generally we don't like lots of external dependencies. External libraries do change over time - would such an entry work 10 years from now? The judges do use and test the entries using different operating systems. What will operating systems look like in 10 years? Having said that :-), if the entry has merit on its own and not just because of the external dependency, then it might "win".

dlowe 14y ago

FWIW, if anyone is curious to see the process of building my entry ("Conway's game of death") I just made the repo public: https://github.com/dlowe/death https://github.com/dlowe/death This contest is great. I'm so glad it's happening regularly again :)

MTGandP 14y ago
A lot of your commit messages don't make any sense. Is there any point at which the program was fully functional but non-obfuscated?
- dlowe 14y ago
  More-or-less yes. I started compressing and obfuscating the code after https://github.com/dlowe/death/blob/7fcbcabb9f69bf0cdfff4651c9a2b8d976898cbf/death.c https://github.com/dlowe/death/blob/7fcbcabb9f69bf0cdfff4651... Sorry about the commit messages. Think of them as part of the obfuscation ;)
lifthrasiir 14y ago
I've also posted the history (or, "scratchpad") of my winning code (2012/kang) to Gist: https://gist.github.com/3909337 https://gist.github.com/3909337 (possible spoilers ahead) Okay, it is quite cryptic and a bit unorganized (as I frantically updated the code as I saw any optimization opportunity), but it may be interesting to see how the code is gradually shorten.
omoikane 14y ago
Process of building my entry is mostly in spoiler.html.gz. For your viewing convenience, it's also here: http://uguu-archive.appspot.com/nyaruko/edit.html http://uguu-archive.appspot.com/nyaruko/edit.html
- dlowe 14y ago
  How did you record that?

saint-loup 14y ago

Fun fact: David Madore, co-author of the conspiratorial contest, actually didn't mean to obfuscate his code. The winner page: http://www.ioccc.org/2012/grothe/hint.html http://www.ioccc.org/2012/grothe/hint.html The source in french: http://www.madore.org/~david/weblog/2012-10.html#d.2012-10-14.2083 http://www.madore.org/~david/weblog/2012-10.html#d.2012-10-1...

customary 14y ago

I must admit I was disappointed in last year's contest winners, namely their general focus. I thought maybe something had been lost in the years the contest was not running. But these entries are great! Binary lambda calculus? Top notch. IOCCC is back! Check this out { echo one;echo two;echo tres;}|./kang result: the sum in hex

ewanmcteagle 14y ago

Seems to be the same John Tromp of the Computer Go bet. http://dcook.org/gobet/ http://dcook.org/gobet/

Evbn 14y ago
Wow, John accurately predicted the year computer Go would beat him, 15 years in advance, and made a $1000 by being slightly conservative. Nice long bet!

venomsnake 14y ago

Amazing entries. These are also the winners for "language you currently hate" clear code contest.