OS X
You can either simply double click the binaries or invoke them from the terminal.
Note that double clicking them actually just creates a terminal window that invokes them. But it does so from your Home folder. It matters because the program will look for files within your Home folder, unless you'll type the full path.
Invoking them manually is preferable because you can specify arguments they are called with. Syntax is:
$ ./PNGStego [path-to-container] [input-file] [key] [--silent]
$ ./PNGDeStego [path-to-container] [output-file] [key] [--silent]
For example:
$ ./PNGStego cats.png passwords.txt el!tepa55word
$ ./PNGDeStego "cats (copy).png" mylovelyhiddenfile el!tepa55word --silent
--silent key turns off any output, unless there's an error that didn't let the program do its job.
Please note that most shells record commands used by default, so it's better to either avoid invoking the program with a 3rd parameter or turn off shell history before doing so / erase shell history after doing so.
First of all, if you intend to modify the source files, please note that there are constants that, if changed, will make your binaries incompatible with others.
If you really want to achieve that, be sure that you have a backup of your binaries / modified source files. Otherwise, you might never extract your data again.
First, you'll need to install Xcode and the libraries PNGStego depends on:
Homebrew makes this task easy:
$ brew install lbzip2
$ brew install lzlib
$ brew install libpng
$ brew install cryptopp
$ brew install boostThen you can either use Xcode or just build it with a terminal.
You'll need to use the Xcode project from this repository. Make a few changes:
Product - Scheme - Edit Scheme...
Build - Build - + - PNGDestego - Add
To ensure that you build both binaries.
File - Project Settings... - Advanced...
To change where Xcode will create binaries. Now you can build the project.
You'll still need to have a compiler obviously. Either install Xcode's command line tools or get yourself gcc from Homebrew.
Execute this in your terminal to build binaries:
$ make