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} /*]]>*/ </style> </head> <body class="mediawiki ltr ns-0 ns-subject page-Obfuscation skin-hawiki"> <div id="topbar" class="noprint"> <div class="portlet noprint" id="p-personal"> <h5>Personal tools</h5> <div class="pBody"> <ul><li><a class="homebutton" href="/web/20170830203204/https://wiki.haskell.org/Haskell">Home</a></li> <li id="pt-login"><a href="/web/20170830203204/https://wiki.haskell.org/index.php?title=Special:UserLogin&returnto=Obfuscation">Log in</a></li> </ul> </div> </div> <div id="p-search"> <div id="searchBody" class="pBody"> <form action="/web/20170830203204/https://wiki.haskell.org/index.php" id="searchform"><div> <input type="hidden" name="title" value="Special:Search"/> <input id="searchInput" name="search" type="text" value=""/> <input type="submit" name="go" class="searchButton" id="searchGoButton" value="Go"/>  <input type="submit" name="fulltext" class="searchButton" id="mw-searchButton" value="Search"/> </div></form> </div> </div> </div> <div id="globalWrapper"> <div class="portlet" id="p-logo"> <a style="background-image: url(/web/20170830203204im_/https://wiki.haskell.org/wikistatic/haskellwiki_logo.png);" href="/web/20170830203204/https://wiki.haskell.org/Haskell"></a> </div> <div id="column-content"> <div id="notice-area" class="noprint">  </div> <div id="content-wrapper"> <div id="p-cactions" class="portlet noprint"> <h5>Views</h5> <div class="pBody"> <ul> <li id="ca-nstab-main" class="selected"><a href="/web/20170830203204/https://wiki.haskell.org/Obfuscation">Page</a></li> <li id="ca-talk"><a href="/web/20170830203204/https://wiki.haskell.org/Talk:Obfuscation">Discussion</a></li> <li id="ca-viewsource"><a href="/web/20170830203204/https://wiki.haskell.org/index.php?title=Obfuscation&action=edit">View source</a></li> <li id="ca-history"><a href="/web/20170830203204/https://wiki.haskell.org/index.php?title=Obfuscation&action=history">History</a></li> </ul> </div> </div> <div id="content"> <a name="top" id="top"></a> <h1 id="firstHeading" class="firstHeading">Obfuscation</h1> <div id="bodyContent"> <h3 id="siteSub">From HaskellWiki</h3> <div id="contentSub"></div> <div id="jump-to-nav">Jump to: <a href="#column-one">navigation</a>, <a href="#searchInput">search</a></div>  <div id="mw-content-text" lang="en" dir="ltr" class="mw-content-ltr">Haskell is (perhaps surprisingly) an excellent language for code obfuscation. There have been three Haskell obfuscation contests: <ul><li> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170830203204/http://www.haskell.org/pipermail/haskell/2004-August/014387.html">1993 Bottomth Obfuscation Haskell Contest</a> </li><li> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170830203204/http://web.archive.org/web/20060103040156/http://iohc.mgoetze.net/">2003 Zeroth Obfuscated Haskell Contest</a> </li><li> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20170830203204/http://web.archive.org/web/20060107141532/http://www.scannedinavian.org/iohcc/succzeroth-2004/">2004 Succ Zeroth Obfuscated Haskell Contest</a> (2004 IOHCC <a href="/web/20170830203204/https://wiki.haskell.org/Obfuscation/IOHCC_2004" title="Obfuscation/IOHCC 2004">announcement</a>) </li></ul> The ability to use symbols for identifiers helps a lot of course, as does suspending the use of layout. <a href="/web/20170830203204/https://wiki.haskell.org/Pointfree" title="Pointfree">Pointfree</a> style is also an excellent help. Use of strange monads and <a href="/web/20170830203204/https://wiki.haskell.org/Type_arithmetic" title="Type arithmetic">type arithmetic</a> can all be very confusing. Finally, Haskell's clean semantics makes refactoring code (semi-)mechanical, leading to some interesting obfuscated encodings (one can replace most Haskell keywords with lambda abstractions, for example). <h2> Example </h2> The following illustrates how, by turning off layout, rewriting keywords (let, case, where) as lambdas, and using symbols for identifiers (in this case multiple '?' characters), Haskell may be highly obfuscated. <div dir="ltr" class="mw-geshi mw-content-ltr"><div class="haskell source-haskell"><pre class="de1"> -------------------------------------------- module Main where{import List;import System; import Data.HashTable as H;(???????)=(concat );(??????)(???)(????)=((groupBy)(???)(????)) ;(??????????????????????)(????)=((?????????? )((tail).(???????))((????????????????????)(( ??????)(?????????????????????)(????))));(??) =([' ']);(??????????????)=((hashString));(?) =((>>=));(???????????????????????)([((???)), (????)])=((?????????????)(???))?(\(?????)->( (????????????????)(==)(??????????????))?(\(( ???))->((??????????????????)(??????????????? )(???)(?????))>>((?????????????????)(???))?( \((?????))->((((???????????????????)((????)) ((??????????????????????))((?????))))))));(( ???????????????????????))(??)=(????????????) ("usage f dic out");(?????????????????????)( (???),(??????))((????),(???????????????????? ))=((???)==(????));(?????????????????)(???)= (toList)(???);(????????????????????)(????)=( ((??????????)(((??????????)(snd)))((????)))) ;(??????????????????)(???????????????)(???)( (?????))=(((mapM)(((???????????????)(???)))( (lines)(?????))));(???????????????????)(???? )(???????????????????????)(?????)=(????????? )(????)((unlines)((???????????????????????)( ?????)));(????????????????)(???)((????))=((( new)(???)(????)));(main)=((???????????)?(((\ (???)->((???????????????????????)(???)))))); (???????????????)(???)(????)=((????????)(??? )((sort)(????))((??)++(????)));(???????????) =(getArgs);(????????????)(???)=((((print))(( ???))));(??????????)(???)(????)=(((map)(???) (????)));(????????)((???))(????)(?????)=(((( H.insert))((???))(????)(?????)));(?????????) ((???))((????))=(((writeFile)(???)((????)))) ;(?????????????)(???)=(((readFile)((???))))} --------------------------------------------</pre></div></div>   </div><div class="printfooter"> Retrieved from "<a href="https://web.archive.org/web/20170830203204/https://wiki.haskell.org/index.php?title=Obfuscation&oldid=20988">https://wiki.haskell.org/index.php?title=Obfuscation&oldid=20988</a>"</div> <div id="catlinks" class="catlinks"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/web/20170830203204/https://wiki.haskell.org/Special:Categories" title="Special:Categories">Categories</a>: <ul><li><a href="/web/20170830203204/https://wiki.haskell.org/Category:Idioms" title="Category:Idioms">Idioms</a></li><li><a href="/web/20170830203204/https://wiki.haskell.org/Category:Contests" title="Category:Contests">Contests</a></li></ul></div></div>  <div class="visualClear"></div> </div> </div> </div></div> <div id="column-one"> <script type="text/javascript"> if (window.isMSIE55) fixalpha(); </script> <div class="generated-sidebar portlet" id="p-navigation"> <h5>Navigation</h5> <div class="pBody"> <ul> <li id="n-mainpage"><a href="/web/20170830203204/https://wiki.haskell.org/Haskell">Haskell</a></li> <li id="n-portal"><a href="/web/20170830203204/https://wiki.haskell.org/HaskellWiki:Community">Wiki community</a></li> <li id="n-recentchanges"><a href="/web/20170830203204/https://wiki.haskell.org/Special:RecentChanges">Recent changes</a></li> <li id="n-randompage"><a href="/web/20170830203204/https://wiki.haskell.org/Special:Random">Random page</a></li> </ul> </div> </div> <div class="portlet" id="p-tb"> <h5>Tools</h5> <div class="pBody"> <ul> <li id="t-whatlinkshere"><a href="/web/20170830203204/https://wiki.haskell.org/Special:WhatLinksHere/Obfuscation">What links here</a></li> <li id="t-recentchangeslinked"><a href="/web/20170830203204/https://wiki.haskell.org/Special:RecentChangesLinked/Obfuscation">Related changes</a></li> <li id="t-specialpages"><a href="/web/20170830203204/https://wiki.haskell.org/Special:SpecialPages">Special pages</a></li> <li id="t-print"><a href="/web/20170830203204/https://wiki.haskell.org/index.php?title=Obfuscation&printable=yes" rel="alternate">Printable version</a></li> <li id="t-permalink"><a href="/web/20170830203204/https://wiki.haskell.org/index.php?title=Obfuscation&oldid=20988">Permanent link</a></li> </ul> </div> </div> </div> <div class="visualClear"></div> <div id="footer"> <div id="f-poweredbyico"><a href="//web.archive.org/web/20170830203204/https://www.mediawiki.org/"><img src="/web/20170830203204im_/https://wiki.haskell.org/wikistatic/skins//common/images/poweredby_mediawiki_88x31.png" height="31" width="88" alt="Powered by MediaWiki"/></a></div> <ul id="f-list"> <li id="lastmod"> This page was last modified on 17 May 2008, at 18:50.</li> <li id="copyright">Recent content is available under <a href="/web/20170830203204/https://wiki.haskell.org/HaskellWiki:Copyrights" title="HaskellWiki:Copyrights">a simple permissive license</a>.</li> <li id="privacy"><a href="/web/20170830203204/https://wiki.haskell.org/HaskellWiki:Privacy_policy" title="HaskellWiki:Privacy policy">Privacy policy</a></li> <li id="about"><a href="/web/20170830203204/https://wiki.haskell.org/HaskellWiki:About" title="HaskellWiki:About">About HaskellWiki</a></li> <li id="disclaimer"><a href="/web/20170830203204/https://wiki.haskell.org/HaskellWiki:General_disclaimer" title="HaskellWiki:General disclaimer">Disclaimers</a></li> </ul> </div> </div> <script>if(window.mw){ mw.loader.load(["mediawiki.user","mediawiki.page.ready"], null, true); }</script> <script src="https://web.archive.org/web/20170830203204js_/https://wiki.haskell.org/load.php?debug=false&lang=en&modules=site&only=scripts&skin=hawiki&*"></script> <script type="text/javascript"> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-83290513-2']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 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