irrFuscator is an obfuscation software that secures AS, MXML, and SWF files for both Flash and Flex. It is equipped with a user-friendly GUI interface, and can also be run from the command line.

One of the key advantages of using irrFuscator is that it is available for the command line, but also comes with a convenient GUI front-end. This gives you the flexibility to use the software in the way that works best for you, depending on your preferences and your level of expertise.
In terms of features, irrFuscator offers a wide range of powerful options. For example, it is able to encrypt strings, as well as obfuscate method, variable, and class names. It can also strip whitespace and do nondeterministic obfuscation. Additionally, it automatically detects references to external flex code, further enhancing its ability to protect your files.
One of the key ways in which irrFuscator helps to protect your files is by addressing a major vulnerability in ActionScript 3 Byte Code. This code still contains a lot of symbols that can reveal how your program works and what it does. This makes it very easy for someone to reverse engineer or steal your code. However, irrFuscator can be used in two modes to prevent this from happening.
The first mode is SWF Obfuscation (Binary), which protects an existing .swf file. The second mode, Flex Obfuscation (Source), reads in a directory of .as and .mxml files, processes them, and puts them out into a target directory. You can simply recompile the directory with the obfuscated files, and your .swf files will be much safer.
Overall, if you are looking for a powerful and easy-to-use ActionScript obfuscator, then irrFuscator is an excellent choice. With its wide range of features, convenient GUI front-end, and strong obfuscation capabilities, you can feel confident that your .SWF files and other code will be well-protected.
Version 2.2.0: added support for Flex 4.5, added support for the Molehill API