irrFuscator

Obsfucation is the process of changing the names of functions, methods, constants, interfaces and classes using a deterministic or not deterministic naming scheme if wished.

irrFuscator is a handy tool that lets you obfuscate the Actionscript 3 bytecode in Flash and Flex SWF files so that decompilers can't extract your function, variable and constant names anymore.

It does this by reading a directory of .as and .mxml files, processing them and putting them out into a target directory. ALl you need to do afterward is simply recompile the directory with the obfuscated files, and your .swf files are a lot safer.

Unlike other similar software tools, irrFuscator doesn't 'encrypt' the SWF, it obfuscates the code, removing all the information from it.  This feature is especially used by big browser games and website developers because of the strong protection irrFuscator provides.

The app was written in C++ and needs approximately 10 seconds to obsfucate one MB of source code on your average PC. In the case of binary SWF file, this time is down to just one second.

One thing worth mentioning is that if you need a symbol to be visible outside of your code or you are using dynamic classes, you can specify any symbol not to be obsfucated.