cxx-obfus - obfuscate (make more difficult to understand) C/C++ source code



NAME

cxx-obfus - obfuscate (make more difficult to understand) C/C++ source code programs


SYNOPSIS

cxx-obfus-v|--version ] [ --noparsing ] [ --output-line-len N ] [ --jam 0|1 ] [ --cxx11-invalid-output ] [ --keep-spaces ] [ --keep-newlines ] [ --keep-comments ] [ --transform-commentstruncate|chars2x|nonwhites2x               |keep-original|replace-with-newlines] [ --bannerhead filename] [--bannertail filename ] [ --excludeidentsfile|-x filename ].. [ --excludeidentsfile-anycase filename ].. [ -X filename ].. [ --suffixes-asis-list filename ].. [ -F user-defined-mapping-filename ].. [ -d map-filename ] [--embed-map] [ -e encode-count ] [ -D list-of-symbols-filename ] [ -i idents-mangling-params ] [ -n number-mangling-params ] [ -s string-mangling-params ] [ -c charcode-mangling-params ] [ -N filename-mangling-params ] [ -S server-mode-params ] [ -O profile-name ] file-to-obfuscate


DESCRIPTION

This program turns C/C++ source code files into functionally equivalent C/C++ source code that is much more difficult to study, analyze and modify - thus providing you control over intellectual property theft. It works perfectly with multi-module programs and for programs that depend on a lot of third-party modules that are not subject to obfuscation.

This program typically obfuscates only one C/C++ source file at a time, reading source code file from stdin and writing output to stdout. It's possble to request it to save the output directly to a file using -o switch. There are special aids to protect several files at once, this is done using multifile ``mode'' - see description of it in the documentation of the -S option below.

All comments are stripped away by default, but this can be switched off by passing the --keep-comments switch. It's possible to add comments with author and copyright information to the top and to the end of the obfuscated version of the file using options --bannerhead and --bannertail respectively. Of course these comments will appear in clear text form in the obfuscated file, independant of whether encoding was applied to it.

The obfuscation typically means

  • replacing all symbol names it's possible to with the non-meaningfull ones, e.g. replacing variable files with zcadaa4fc81, while preserving synaxical and semantical correctness of the source code. Of course predefined symbols like document and symbols from the third-party or standard libraries the source code uses will be left the same so the obfuscated code will still work without requiring to obfuscate those third-party and standard libraries.

  • substitution of numeric values with the arithmetic expressions using (random or constant for the same numeric value as requested by the options) decimial and hexadecimial numeric values that evaluate to the same value

  • using hexadecimial character codes for all characters in strings

  • removing extra white space

  • jamming as much code on each line (of length not more than specified using --output-line-len option) as possible if --jam=0 is not specified

The non-encoded obfuscated code is extremely difficult to understand for a human since the name of variables and subroutines and other symbols are totally meaningless and hard to remember (e.g. files becomes zcadaa4fc81). It's possible to control most aspects of obfuscation using the commandline switches of the CXX-Obfus.

It's possible to request CXX-Obfus to save the mapping between obfuscated symbol names and original symbol names in the external file by passing the filename after -d switch.


OPTIONS

It's possible to store the default commandline options in the globally-visible file $instroot/lib/cxx-obfus/cxx-obfus-settings.pl (where $instroot is a directory in which the CXX-Obfus package was installed to). See comments in that file for more information.

Note that there is interacive web-based commandline builder for CXX-Obfus available at http://www.stunnix.com/support/interactive/cmd-builder/.

-v|--version
Output version information and exit.

--output-line-len N
Set the maximum line length for the obfuscated file. However, if some string constant will be longer than this limit, it won't be split or otherwise wrapped, resulting in a line longer than an amount specified. The default value for parameter N is 80.

--jam 0|1
Control whether to omit extra white spaces. When argument is 1, all extra white spaces (including carridge returns) are omitted, that makes the obfuscated file looking even less readable. When argument is 0, the obfuscated (but not encoded) file will look like original file with respect to spaces and newlines - in particular it will have the same identation. By default jamming is enabled (value is 1).

--cxx11-invalid-output
Allow to produce more compact code, but that is invalid C++11 code. By default, valid C++11 code is produced.

--keep-spaces
Request not to skip extra spaces in the lines (whitespaces and tabs) if jamming is enabled (which is the default). By default extra spaces in the line are ignored if jamming is enabled.

--keep-newlines
Request not to skip newlines if jamming is enabled (which is the default). By default newlines are ignored if jamming is enabled.

--keep-comments
Requests to keep all comments. By default all comments are stripped away.

--transform-comments replace-with-newlines|truncate|chars2x|nonwhites2x|keep-original
If --keep-comments is specified on the commandline, this option specifies what to do with comments. By default comments are not modified (this corresponds to value keep-original of this option). The possible values for this option are:
replace-with-newlines
If specified, comment delimiters and their bodies are removed, and are replaced with newlines contained in the comment bodies (thus keeping line numbers in sync with original code, but not revealing locations where comments were located).

truncate
If specified, only newlines are kept in bodies of comments.

chars2x
If specified, newlines are kept in bodies of comments, and all other characters including spaces are replaced with character 'x'. This is useful to show that original code contained some comments, and give an impression on what length of them was.

nonwhites2x
If specified, newlines are kept in bodies of comments, and all other characters except whitespaces are replaced with character 'x', whitespaces are left as is. This is useful to show that original code contained some comments, and give an impression on what length of them was, and what content they had approximately (since a lot of comments in the code happen to be various separators formed by repeating some character like dash for entire length of the line).

keep-original
If specified, comments are kept as they were in original code. This is a default value for this option.

--bannerhead filename
--bannertail filename
Specify the file whoose content will be prepended or appended to the obfuscated file. This is most useful for adding comments with copyright and license information. Such comments will be visible as clear text in any file that was obfuscated and/or encoded.

-o destination-filename
Output the obfuscated version to the named file. There is no default value for this option - i.e. the obfuscated file is written to stdout by default.

--excludeidentsfile filename
-x filename
This option can be specified more than once. It allows to specify the names of files that contain a list of symbol names that won't be mangled, one symbol per line. Such symbols are called exceptions from this point. Comments are allowed in such files by placing a hash sign (#) as the first character of the line. The file name specified is first searched in the current directory (if it's not absolute path), and then in the subdirectory lib/cxx-obfus/exceptions/ of the directory where CXX-Obfus was installed to. There is no need to add names of C/C++ pre-defined variables and functions - they are already hardcoded into CXX-Obfus. The default set of exceptions CXX-Obfus uses can be controlled in the file that stores ``persistent settings'' for it - located in the lib/cxx-obfus/cxx-obfus-settings.pl in the directory where CXX-Obfus was installed.

It's possible to remove symbols from lists of exceptions by passing names of files with these symbol names using -X switch.

The filename can be name of directory, in this case all files located in this directory and any of its subdirectories (at any depth) are loaded as if the names of these files were specified individually one-by-one.

--excludeidentsfile-anycase filename
This option is very similar to --excludeidentsfile, except that symbols read from the specified file are treated as case-insensitive exceptions. This functionality is useful for listing methods and properties of ActiveX objects, that are case-insensitive.

The filename can be name of directory, in this case all files located in this directory and any of its subdirectories (at any depth) are loaded as if the names of these files were specified individually one-by-one.

-X filename
This option can be specified more than once. It allows to specify the names of files that contain a list of symbol names that should be mangled, even if those symbol names were in the files with names passed with -x switch (i.e. for disabling some exceptions). At first files specified with -x switch are processed, and then files specified with -X switch are processed.

Comments are allowed in such files by placing a hash sign (#) as the first character of the line. The file name specified is first searched in the current directory (if it's not absolute path), and then in the subdirectory lib/cxx-obfus/exceptions/ of the directory where CXX-Obfus was installed to.

This option is mostly useful in case the set of exceptions created from builtin list and content of files passed with -x switch is too broad.

The filename can be name of directory, in this case all files located in this directory and any of its subdirectories (at any depth) are loaded as if the names of these files were specified individually one-by-one.

--suffixes-asis-list filename
This option can be specified more than once. It allows to specify the names of files that contain a list of suffixes that should be preserved in symbols being mangled. E.g. if suffix onclick is listed in some file mentioned by this option, then symbol myButton_onclick will be mangled to something like z2b9a0ec6d_onclick, rather than to something like za40f93e635d.

Comments are allowed in such files by placing a hash sign (#) as the first character of the line. The file name specified is first searched in the current directory (if it's not absolute path), and then in the subdirectory lib/cxx-obfus/exceptions/ of the directory where CXX-Obfus was installed to.

This option is mostly useful for protecting code for environments, that scan name of symbol for some suffix in order to treat the symbol specially.

The filename can be name of directory, in this case all files located in this directory and any of its subdirectories (at any depth) are loaded as if the names of these files were specified individually one-by-one.

-F user-defined-mapping-filename
This option can be specified more than once. It allows to specify the names of files that contain user-specified mapping of symbols.

Comments are allowed in such files by placing a hash sign (#) as the first character of the line. Each line in such file contains two symbols: name of original symbol, one or more space characters, and required resultant symbol.

In case some mangling engine decides to assign a symbol that is listed as resultant symbol, special attempts will be made to guarantee that the symbol chosen by obfuscation engine won't conflict with it (by adding prefixes until unqueness is reached).

-d map-filename
This option specifies the name of file to write the mapping between obfuscated symbol names and non-obfuscated symbol names to. Such mapping may be useful for analyzing C/C++ error messages that contain obfuscated symbol names - just find the line with the symbol C/C++ interpreter complained about, and the second word on that line will be the original symbol name. Please keep in mind that it will be much easier for a person having access to such mapfile to study the code, so it's highly suggested to keep such map file in secure place and not to distribute it to the customers.

If the file specified with this option exists, the accumulated mapping information will be merged with mapping information previously stored in the file - this allows one to have map file for entire project.

By default no filename is specified, and thus mapping information is not saved anywhere.

--embed-map
This option instructs the mapping between obfuscated symbol names and original symbol names to be appended inside a comment to the result of processing, in form of couple of strings per line - obfuscated symbol name and original symbol name. For symbols that are exceptions (i.e. for ones obfuscated symbol name is the same as original) such lines are not emitted at all. Lines are emitted only for symbols found in subject file.

By default this mapping information is not embedded at all.

-D list-of-symbols-filename
Instructs CXX-Obfus to save a list of symbols encountered during processing to the list-of-symbols-filename. The file will be overwritten. This is useful e.g. when generating a list of exceptions from some library, since the resultant file can be used for passing to -x or -X switches while processing files that use that library.

.

-i idents-mangling-params
-n number-mangling-params
-s string-mangling-params
-N filename-mangling-params
Specify options for mangling of tokens of each type. The argument is mangling-specification, that has the following syntax:

obfuscator-title[,option=value]..

Tokens of each type can be mangled using different approaches, each approach corresponds to obfuscator, identified by obfuscator-title. Each obfuscator can have options that alter its behaviour, in order to specify them the comma separated option=value pairs may follow obfuscator-title after a comma.

The mangling-specification specifies all details on how to mangle tokens of each type, so if multiplie occurences of the option are specified, the last one is taken into the effect.

For each type of token a special obfuscator with title none is available - it doesn't alter the tokens in any way.

Here is a list of obfuscators for each type of the token, with the options they support.

-i = obfuscators for symbol names
It's obvious that symbols with the same name should be obfuscated to the same name, independant of location in the program these symbol names are locatged. It also should be obvious that entire set of modules and scripts that uses them should be obfuscated using the same value of mangling-specification - otherwise there will appear undeclared symbols.
obfuscator none
Selecting this obfuscator will keep symbol names unchanged.

obfuscator combs
This obfuscator replaces names of symbols with names consisting of all possible combinations of characters, specified via option spec, of the length specified via option minlen. E.g. it can replace formname with IlI and mystr with llI (which both look very similar to the human eye) if user specified the value of spec option as Il. The resulting symbol name depends only on original symbol name and the value of seed option, calculation of some md5 sum of the string formed from these two items is used to generate resultant symbol name. The md5 algorithm can produce same sum value for different arguments - in which case so-called md5sum-collision occurs. The detection of collisions for symbols in the current file is done automatically. It's possible to activate detection of collisions for symbols in entire project by the use of adhere-mapfile option of this symbol obfuscator. If option adhere-mapping is specified for this obfuscator and has non-zero value and if mapfile name is specified via global option -d, then CXX-Obfus will read specified mapfile at startup, and will try to lookup the original symbol names in it and use a replacement from that file if found; it will also ensure that protected symbols that were produced during that invokation of CXX-Obfus are not assigned to any symbol listed in mapfile (and if it encounters some obfuscated symbol it was going to use as a replacement as being used as a replacement for another symbol (i.e. so-called ``hash-collision'' occurs) then execution of CXX-Obfus is aborted with error message - in which case it's necessary to clear mapfile, change the seed and/or increase value of len option and protect entire application again); after processing completes, mapfile will be updated as usual. Note, that shortest symbol obfuscator also can generate protected symbols using all possible combinations of characters, but it allows to generate shortest names possible at the same time (by requiring 2 passes on each source file).

Options:

adhere-mapfile
See description of combs obfuscator for more information on this option. The default value is 0.

seed
The value of this option affects the order in which all possible combinations of characters used for symbol name are chosen. The value can be arbitrary string.

minlen
len
Minimal length of generated symbol. Once all combinations of characters of a given length were used for generating symbol names, the length of resultant symbol name is automatically increased. This means it's not necessary to make the value of this option very long - set it to big enough value that makes your code acceptably unreadable and acceptably big. It's impossible to assign value lower than 4 to this option. The default value is for this option is 10.

spec
The value of this option instructs which characters can be used for generating names of symbols, the value should either be string that is a concatenation of all characters possible in the resultant symbol name, e.g. Il or OQ, or a couple of such strings separated by colon, in which case a string before the colon specifies characters that can be used for leading symbol's character, and string after the colon specifies characters that can be used for all characters of the symbol except the first (the leading) - e.g. lI:lI1 or O:O0. The recommended values are lI, O:O0 and lI:lI1. If this option is not specified, it's assumed that all characters allowed for C/C++ language to be used for symbols can form a resultant symbol name.

obfuscator md5
This obfuscator calculates md5 sum of the string produced by concatentation of a constant prefix (that can be passed via seed option) and the symbol name to be obfuscated. After that from the hexadecimial representation of the md5sum several (exact length is specified using len option) leading characters are appended to another prefix (that can be set via prefix option) to form obfuscated symbol name.

It's obvious that in theory it's possible to get md5sum collision - the critical situation when two different symbols will be obfuscated to the same symbol name. When such situation is detected, the obfuscation is aborted. The detection of collisions for symbols in the current file is done automatically. If detection of collisions for symbols in entire project is required, one can use adhere-mapfile option for enforcing uniqueness of protected symbols across all files - please read the description of symbol name obfuscator combs. The only solution in case md5sum collision is detected is to change the value of the seed option or to increase the value of the len option. However, such situations are very rare.

This is the default obfuscator for symbol names.

Options:

adhere-mapfile
See description of combs obfuscator for more information on this option. The default value is 0.

seed
See above for a description of this option. The value can be arbitrary string. The default value is generated as random string at the CXX-Obfus suite installation time, so it will be unique for each user of CXX-Obfus.

len
Specifies how many characters of the hexadecimial representation of the md5 sum to use for obfuscated name of the symbol. The less the value, the shorter all identifiers will be, the smaller obfuscated code will become, and the easier it will be for human to study the code. Also increasing the value lowers the probability of md5sum collision. The default value is 10.

prefix
Specifies the prefix of all mangled symbol names. It should non-empty string (one character is enough) just because hex representation of md5sum can begin with a digit. There is no point in changing the prefix. The default value is z.

obfuscator prefix
This obfuscator just prepends the same string (specified via str option) to all symbol names to get the obfuscated symbol name. This obfuscator is designed to be used for initial testing of obfuscated code for locations of use of undeclared symbols in obfuscated code. It's obvious that while testing obfuscated code it's much more easier to find out what symbol is undeclared if it's trivial to correlate that symbol of the obfuscated program with the symbol of the non-obfuscated program.

Options:

str
The string to prepend to all symbol names. Default value is Z439Z_.

obfuscator shortest
This obfuscator replaces each symbol name with the shortest identifier possible, using the shorter identifiers for symbols that are used more times. Using this obfuscator and none obfuscators for strings and numbers will produce the most compact version of the code possible, that will be smaller than the original one. The presence of this obfuscator turns CXX-Obfus into so-called source code ``compressor''.

It's perfectly suitable for multimodule projects too. There are two modes of operation this obfuscator works in (controlled by its parameter countupdate) - scanning through the project files for computing the use counts for all symbols (used if parameter countupdate is passed value 1) and saving the counts to a special file hereafter called countsfile (whose name is specified as value of parameter countsfile) or performing the obfuscation itself using the symbol use counts from countsfile gathered during first mode of operation (used if parameter countupdate is passed value 0, or if this parameter is not specified at all). In the obfuscation mode obfuscator maintains its state (a mapping between original symbols and obfuscated ones) in the file whose name specified as a value of parameter statefile (hereafter such file will be called statefile).

Note that file with symbol counts should be uptodate - at least it should mention all symbols that are subject to obfuscation - so if you added some code and introduced some new symbol, you'll have to regenerate countsfile. CXX-Obfus aborts execution if it encounters that some symbol was not counted at all, with diagnostics indicating that countsfile needs to be rebuilt. Rebuilding countsfile means deleting (or truncating) the countsfile and statefile and running CXX-Obfus in symbol count gathering mode on all files of the project. If your change to the code didn't introduce new symbols but just increased or decreased the use of already existing ones, it won't abort the execution but there will be a chance that size of resultant obfuscated file won't be the smallest possible.

So the common approach to using this obfuscator for symbol names is: develop and debug the code, delete files a-file-with-counts and a-file-with-state, then run the CXX-Obfus with options like this -i shortest,countupdate=1,countsfile=a-file-with-counts for all source files in the project to gather symbol counts to the file a-file-with-counts, and then run CXX-Obfus with options like this -i shortest,countupdate=0,countsfile=a-file-with-counts,statefile=a-file-with-state for all source files in the project.

By default each symbol name is obfuscated to the unque, but random identifier of the length corresponding to the number of occurencies of the given symbol. That randomness of identifier can be disabled by passing value 0 for parameter dontshuffle - this will force e.g. first symbol in the first source file of the project to always be obfuscated to the name a (provided there is no exception with the same name).

It's possible to specify a set of characters that can be used for resultant symbol names by the use of spec option - e.g. one can make code very hard to analyze without modification by asking to use only symbols I and l for names of symbols - that will produce symbols like IllII or IIlIIl which look very similar in the most fonts (but of course this won't result in smallest output). The use of this option makes shortest obfuscator a reliable version of combs obfuscator for multi-module projects, since it eliminates a chance for a case when two different symbols in two different modules (in which only one of the symbols is used) getting replaced with the same resultant symbol (which is possible in theory, but has a very small possibility).

Options:

countsfile
Location of the countsfile - the file containing use counts for all symbols.

countupdate
Selects the mode of obfuscator - gathering symbol use counts (if value is 1) or obfuscating (value is 0). Default value is 0.

statefile
Specifies the name of the file with the state information used internally by obfuscator when it's in obfuscation mode.

dontshuffle
Instructs not to select random name of the given length as obfuscated symbol name, but to select the next one by alphabet not being an exception.

minlen
Instructs the minimal length of resultant symbol name. Default value is 1.

spec
The value of this option instructs which characters can be used for generating names of symbols, the value should either be string that is a concatenation of all characters possible in the resultant symbol name, e.g. Il (that will produce symbols like IllII or IIlIIl) or OQ (that will produce symbols like OQOOQQ or QOOQQO), or a couple of such strings separated by colon, in which case a string before the colon specifies characters that can be used for leading symbol's character, and string after the colon specifies characters that can be used for all characters of the symbol except the first (the leading) - e.g. lI:lI1 (that will produce symbols like I1lII1 or lI1IIl1) or O:O0. The recommended values are lI, O:O0 and lI:lI1. The use of this option makes shortest obfuscator a reliable version of combs obfuscator for multi-module projects. If this option is not specified, it's assumed that all characters allowed for C/C++ language can form a resultant symbol name.

-n = obfuscators for numeric constants
There is only one non-trivial obfuscator for numeric constants currently - sum3. It's the default.
obfuscator none
Selecting this obfuscator will keep numbers unchanged.

obfuscator sum3
This obfuscator replaces the constant value with an arithmetic expression consisting of addition and substraction operations on either 3 constant numeric values (in case no asserters were enabled) or 2 constant numeric values and 1 constant variable (in case some asserters were enabled - please note that asserters are not supported in Trial version of the Product), which are represented as decimial and hexadecimial values (their radixes can be changed by altering format option). For different occurencies of the same constant numeric values, the choice is provided between using the same values used in expressions, or using 2 random values and one computed - this is controlled using const option. If you wish to make analysis of the differencies between revisions of your software more difficult, you should request the use of 2 random values and one computed in the expression - this way after each obfuscation each obfuscated file will differ from the previous run of obfuscator. This is the default obfuscator (in fact it's the only non-trvial one for numeric constants).

Options:

const
Specifies whether for the same numeric constant the obfuscation should produce different substitution expression (the value for the option is 0) or same expressuib (the value for the option is 1). Default value is 0.

format
Specifies the sprintf format string for the obfuscated substitutor. The default value is (0x%04x+% 4d-0x%04x).

-s = obfuscators for string constants
These make constant strings more difficult to read. The default string obfuscator is hexchar. The default string obfuscator is none - that is, strings are not mangled at all.
obfuscator none
Selecting this obfuscator will keep strings unchanged.

obfuscator hexchar
This obfuscator substitutes each character of the string with reverse slash and it's code, by default in hexadecimial notation - e.g. string ``abc'' is substituted with ``\x61\x62\x63''.
format
Specifies the sprintf format string for each character's substitutor. The default value is '\\x%x'.

-N = obfuscator for file names
Please read the description of the ident obfuscator for identifiers. md5, combs, prefix and none obfuscators are supported, they basically have the same options.

Below are options that specific to mangling of filenames.

filename-policy
For md5 and combs manglers, it specifies which part of file path is used to generate a new name of file (without path!). Given same part of file path, you will get same resultant file name. Use this to control whether files with same name, residing in different directories, should get different resultant names, and so on.

dirname-policy
For md5 and combs manglers, it specifies which part of directory path is used to generate a new name of directory. I.e. should subdirectories with same name, residing in different directories, get same or different resultant names.

sysdir-file-mangling
This option controls whether name of file specified using #include < > be subject to filename mangling. So if you have time.h in your project, and have a #include <time.h> line in your code, depending on this option that line will be either updated (and resultant name of time.h present in your project be used) or whether it will be left unmodified. Set it to 1 for projects that use #include < > to refer to their own files.

lowercase-before-mangling
This option controls whether name of file or folder is lowercased before applying mangler to it. If you mix case of filenames in your project (e.g. if you refer to MyFile.h as myFile.h and myfile.h in different places via #include directive, then you have to have this option enabled). By default it's enabled.

alter-filenames
alter-dirnames
These options are accepted only by prefix filename mangler. They allow you to control separately altering names of files and directories. This is handy when debugging your scripts and Makefiles. Note, that md5 and combs manglers allow to turn of mangling names of files or names of directories using filename-policy and dirname-policy (pass nochange to disable altering names of files or directories).

-S server-mode-params
Specify options for server mode backends. The argument is server-specification, that has the following syntax:

server-backend-title[,option=value]..

There are several types of backends. The backend is selected by server-backend-title. Each backend can have options that alter its behaviour, in order to specify them the comma separated option=value pairs may follow server-backend-title after a comma.

There is a special backend with title none available - it doesn't perform any action other than processing selected input file (i.e. it doesn't have any server behaviour).

When non-default backend is used, CXX-Obfus waits for input coming from a backend-specific source, processes input according to commandline options given to it when CXX-Obfus was started (this means that the same set of exceptions and other processing options will be used for all supplied inputs), and returns the result of processing in the backend-specific way to the client (or stores them somewhere).

Here is a list of server-backend-titles, with the options they support.

none
When it's selected, CXX-Obfus will read input file from stdin or from file whose name is passed as a commandline argument, and will produce output on stdout or to the file specified with -o option. This server mode has no options. This is default server mode.

multifile
This server mode allows to process several files with the same set of commandline options at once. The names of files are passed as commandline arguments of CXX-Obfus or via filelist parameter; they may be located in different directories. The name of the output directory is specified with outdir option of this server mode; if filenames to process are absolute pathnames it's necessary to specify input directory relative to which output filenames will be computed by the use of option indir. If filenames to process are relative names, it's assumed that current directory is input directory relative to which output filenames will be computed. All necessary output subdirectories will automatically be created.

Example:

The following commandline fragments:

    -S multifile,outdir=/home/user/prj1/out,indir=/home/user/prj1/in         /home/user/prj1/in/file1..cpp /home/user/prj1/in/file2..cpp         /home/user/prj1/in/subdir1/file3..cpp

and

    -S multifile,outdir=/home/user/prj1/out         file1..cpp file2..cpp subdir1/file3..cpp

are equivalent if current directory is /home/user/prj1/in. So at first CXX-Obfus will create /home/user/prj1/out/subdir1 (if absent), and will put protected version of file1..cpp to /home/user/prj1/out/file1..cpp, file2..cpp to /home/user/prj1/out/file2..cpp and subdir1/file3..cpp to /home/user/prj1/out/subdir1/file3..cpp.

Options supported:

outdir
This option is required; it specifies the output directory.

indir
This option specifies base input directory used to compute input file names (see example above); specifying this option is not necessary if all input filenames specified are relative.

filelist
This option specifies name of file that contains filenames to process, one per line. Filenames should be relative to the directory specified by indir parameter. This is not mandatory option - if it's not specified, names of files to process are taken from the command line.

-O profile-params
Tune the behaviour of the CXX-Obfus for some specific dialect or environment.

The argument is profile-params, that has the following syntax:

profile-name[,option=value]..

There are several profiles available. The profile is selected by profile-name. Each profile can have options that alter its behaviour, in order to specify them the comma separated option=value pairs may follow profile-name after a comma.

The following values for profile-name are available:

default
Selects default C/C++ dialect.

The profile with name default is the default profile.

All profiles have the following options (specified in the way options for manglers and extractors are specified):

handle-dynamic-scripts
Specifies whether dynamic C/C++ code (the code generated on the fly) should be obfuscated. See the description of the option with the same name for asp extractor.

dynamic-scripts-by
Specifies names of objects and methods whoose arguments should be scanned for dynamic C/C++ code. See the description of the option with the same name for asp extractor.


RETURN VALUE

In case of an error, the exit code will be non-zero, otherwise the exit code will be zero.


DIAGNOSTICS

On successful processing of the file its obfuscated and/or encoded version will be printed to stdout or saved to file specifed with -o commandline option. The processing will stop if there is a syntax error in the file being obfuscated or in the file it uses - in that case location and details of syntax error will be printed to stderr.


EXAMPLES

The following commandline obfuscates and encodes file blah..cpp using default parameters and exceptions from file named ./excepts, writing obfuscated and encoded version to oblah..cpp:

    cxx-obfus blah..cpp -o oblah..cpp -x ./excepts

The following commandline is recommended way of obfuscating file blah..cpp for shipping using default parameters and exceptions from file named ./excepts, writing obfuscated and encoded version to oblah..cpp (the main difference from previous example is passing the value of the seed parameter for obfuscator routine for symbol names):

    cxx-obfus blah..cpp -o oblah..cpp -x ./excepts -i md5,seed=SomeRandomString

The following commandline is a recommended for producing the mildly-obfuscated non-encoded version of the blah..cpp that is ideal for testing whether the obfuscated code has no problems like use of undefined symbols (that may arise due to insufficiently complete list of exceptions in file ./excepts) :

    cxx-obfus blah..cpp -e 0 -o oblah..cpp -x ./excepts -n none -s none -i prefix,str=ZZZ

The following commandlines are a sample of passing same set values for all options to the md5 obfuscator routine for symbol names. It obfuscates and encodes file blah..cpp, writing obfuscated and encoded version of the file to oblah..cpp:

    cxx-obfus blah..cpp -o oblah..cpp -i md5,seed=57823,prefix=p,len=5
    cxx-obfus blah..cpp -o oblah..cpp -i 'md5,prefix=p, seed=57823 , len=5'

The following example obfuscates and encodes file blah..cpp, writing obfuscated and encoded version of the file to oblah..cpp, with embedding code for license checking that allows the code to be executed itself till 28 April 2005; upon expiration of the code default message is printed:

    cxx-obfus blah..cpp -o oblah..cpp 
        -T 'expire,whenexpires=28 April 2005,onviolated-warn=1' 
        -H hosttails,matches=site.com+.site.com,onviolated-warn=1


FILES

It's possible to store the default commandline options in the globally-visible file $instroot/lib/cxx-obfus/cxx-obfus-settings.pl (where $instroot is a directory in which the CXX-Obfus package was installed to) which is a Perl module. This file defines one sub cmnargs that should return a list of options to be prepended to actual commandline the cxx-obfus, thus allowing to store ``persistent settings'' for cxx-obfus.


NOTES

In most cases, once properly prepared for obfuscation, obfuscated version of the code should work the same as non-obfuscated. After fixing the issues with incomplete set of exceptions, it's recommended to check whether ofbuscated code behaves exactly the same as original - by using pre-existing testsuite or checking functionality manually.

If some obfuscated code is syntaxically correct but works differently than original version , obfuscate it without encoding and string, integer and ident mangling as following:

Then try to run it again. If it still does not work correctly, find the source file which is guilty by replacing each of the obfuscated files with original ones one by one. After you have found the file that contains the problem, append the definitions of all functions from the source file to that target file and by temporary renaming function names in the appended part to something else (e.g. by suffixing the names with '1' or 'blah') you will be able to find the function that is guilty. Same process can be applied to the blocks in the guilty function too (just replace obfuscated parts with source parts) to find out which part of the obfuscate function is misbehaving.

Having found the function block that misbehaves, that block should be modified in order the obfuscated version to have the same functionality as original code.