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Obfuscated codeObfuscated code is source code that is (perhaps intentionally) very hard to read and understand. Some languages are more prone to obfuscation than others. C, C++ and Perl are most often cited as easily obfuscatable languages. Macro preprocessors are often used to create hard to read code by masking the standard language syntax and grammar from the main body of code.There are also programs known as obfuscators that may operate on source code, object code, or both, for the purpose of deterring reverse engineering.
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Code is sometimes obfuscated deliberately for recreational purposes. There are programming contests which reward the most creatively obfuscated code: The International Obfuscated C Code Contest, Obfuscated Perl Contest[?] and Obfuscated PostScript Contest[?].
There are many varieties of interesting obfuscations ranging from simple keyword substitution, use/non-use of whitespace to create artistic effects, to clever self-generating or heavily compressed programs.
Short obfuscated Perl programs printing "Just another Perl hacker" or something like that are often found in signatures of Perl programmers. See: Just another Perl hacker.
Take this infamous example from 'net lore:
#include <stdio.h>
main(t,_,a)char *a;{return!0<t?t<3?main(-79,-13,a+main(-87,1-_,
main(-86,0,a+1)+a)):1,t<_?main(t+1,_,a):3,main(-94,-27+t,a)&&t==2?_<13?
main(2,_+1,"%s %d %d\n"):9:16:t<0?t<-72?main(_,t,
"@n'+,#'/*{}w+/w#cdnr/+,{}r/*de}+,/*{*+,/w{%+,/w#q#n+,/#{l+,/n{n+,/+#n+,/#\
;#q#n+,/+k#;*+,/'r :'d*'3,}{w+K w'K:'+}e#';dq#'l \
q#'+d'K#!/+k#;q#'r}eKK#}w'r}eKK{nl]'/#;#q#n'){)#}w'){){nl]'/+#n';d}rw' i;# \
){nl]!/n{n#'; r{#w'r nc{nl]'/#{l,+'K {rw' iK{;[{nl]'/w#q#n'wk nw' \
iwk{KK{nl]!/w{%'l##w#' i; :{nl]'/*{q#'ld;r'}{nlwb!/*de}'c \
;;{nl'-{}rw]'/+,}##'*}#nc,',#nw]'/+kd'+e}+;#'rdq#w! nr'/ ') }+}{rl#'{n' ')# \
}'+}##(!!/")
:t<-50?_==*a?putchar(31[a]):main(-65,_,a+1):main((*a=='/')+t,_,a+1)
:0<t?main(2,2,"%s"):*a=='/'||main(0,main(-61,*a,
"!ek;dc i@bK'(q)-[w]*%n+r3#l,{}:\nuwloca-O;m .vpbks,fxntdCeghiry"),a+1);}
Although pretty unintelligible at first glance, it is a legal C program which when compiled and run will generate the 12 verses of The 12 Days of Christmas. It actually contains all the strings required for the poem in an encoded form inlined in the code. The code then iterates through the 12 days displaying what it needs to.
Another example is a program's source listing that was formatted to resemble an empty tic-tac-toe board. Each pass through the program modified the sourcecode to show a turn in the game, to be executed for the next move.
One definition of "code obfuscation" is a set of transformations on a program, that preserve the same black box specification while making the internals difficult to reverse-engineer. There turns out to be many such transformations.
For example, dynamic languages such as Java, C#, and Lisp store a program's symbol table within the compiled output. One common obfuscation is to rename every class from something descriptive like "Encryption_Index", to a meaningless sequence such as "rb". The class methods can be renamed to a(), b(), etc.
When writing source code, programmers generally create a great deal of structure, according to rules from Structured Programming, OOP, and other methodologies. Compilers tend to propagate this structure into compiled code. The job of a good obfuscator is to destroy as much as possible of this structure that lends a program to being human-readable.
Even when a language is compiled to an executable or bytecode file, someone may choose to run a decompiler which converts these files back into human-readable form (generally sans comments).
This could help them understand whatever lies hidden within the source code, against the wishes of the code's creator.
Obfuscation serves to increase the difficulty of decompilation, usually forcing someone who wants that information to use more costly forms of reverse engineering.
Obfuscation usually breaks down structures which make programs modular and maintainable. This has the pleasant side-effect of reducing code size in many cases. For example, in dynamic languages that incorporate a symbol table with the executable code, simple variable renaming can save a great deal of space in the resulting code footprint. This is a crucial consideration if code size must be kept to a minimum, as with code that must be sent over a network or embedded into a small device.
Obfuscated code is extremely difficult to debug. Variable names will no longer make sense, and the structure of the code itself will likely be modified into unrecognizability. This fact generally forces developers to maintain two builds: One that can be easily debugged, and another for release. Both builds should be tested to make sure they act identically.
Occasionally an obfuscator may be buggy, in a difficult to reproduce way. There is little one can do except find or create a newer version or fiddle with any inputs to the obfuscator until it magically works.
Reflection[?] is a set of APIs in various languages that allow an object to be examined or created just by knowing its classname at run-time. Many obfuscators allow specified classes to be exempt from renaming; and it is also possible to let a class be renamed and call it by its new name. However, the former option places limits on the dynamism of code, while the latter adds a great deal of complexity and inconvenience to the system.
Sibley
THE secret.html">secret.html">secret.html">secret of the stars-- gravitation.
The secret of the soil-- to receive seed.
The secret of man-- the sower.
My secret: Under a mound that you shall never find.
Adam Weirauch
I WAS crushed between Altgeld and Armour.
Fighting for Altgeld whom Editor Whedon
Then Armour started to ship dressed meat to Spoon River,
And my butcher shop went all to pieces.
At the same time. I thought it due me, to recoup the money I lost
For the Governor to appoint me Canal Commissioner.
So I ran for the legislature and was elected.
On Charles T. Yerkes' street-car franchise.
Who was it, Armour, Altgeld or myself
A chaplain in the prisons,
Drunk with divinity, Spoon River--
And myself to scorn and wretchedness.
And even love of wine,
Reaches the ecstatic vision
Only after many trials for strength,
Does the aspiring soul
Find the divine
In a forgotten place near the fence
Have crept over, growing sparsely.
The wife of a noted millionaire,
Beautiful, admired, magnified perhaps
You have succeeded,
You are alive, I am dead.
And I know that lying here far from you,
In the brilliant world where you move,
That robs it of complete triumph.
John Hancock Otis
As to democracy, fellow citizens,
That l, who inherited riches and was to the manor born,
In my devotion to the cause of Liberty?
Born in a shanty and beginning life
Then becoming a section hand when he was grown,
To the superintendency of the.
On
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