How can I obfuscate (protect) JavaScript? [closed]

Question

I want to make a JavaScript application that's not open source, and thus I wish to learn how to can obfuscate my JS code? Is this possible?

Answer 1

If you use a JavaScript library, consider Dojo Toolkit which is compatible (after minor modifications) with the Closure Compiler's Advanced mode compilation.

Dojo – The Only JavaScript Library Compatible with The Closure Compiler

Code compiled with Closure Advanced mode is almost impossible to reverse-engineer, even passing through a beautifier, as the entire code base (includinhg the library) is obfuscated. It is also 25% small on average.

JavaScript code that is merely minified (YUI Compressor, Uglify etc.) is easy to reverse-engineer after passing through a beautifier.

Answer 2

You can obfuscate the javascript source all you want, but it will always be reverse-engineerable just by virtue of requiring all the source code to actually run on the client machine... the best option I can think of is having all your processing done with server-side code, and all the client code javascript does is send requests for processing to the server itself. Otherwise, anyone will always be able to keep track of all operations that the code is doing.

Someone mentioned base64 to keep strings safe. This is a terrible idea. Base64 is immediately recognizable by the types of people who would want to reverse engineer your code. The first thing they'll do is unencode it and see what it is.

Answer 3

I would suggest first minify with something like YUI Compressor, and then convert all string and numbers to HEX Values using something like http://www.javascriptobfuscator.com/

With this, the code would be rendered near impossible to understand and I think at this Stage it will take more time for a Hacker to re-enact your code than actually if he re-wrote from scratch. Rewriting and Cloning is what you cant actually stop. After all we are free-people !

Answer 4

You definitely should consider taking a look at Obfuscriptor.

I goes beyond the typical Javascript minifying tricks we've seen from other tools such as YUI Compressor or Google Closure.

The obfuscated code looks more like encrypted. Unlike anything I've seen before.

Answer 5

This one minifies but doesn't obfuscate. If you don't want to use command line Java you can paste your javascript into a webform.

Answer 6

Dean Edward's Packer is an excellent obfuscator, though it primarily obfuscates the code, not any string elements you may have within your code.

See: Online Javascript Compression Tool and select Packer (Dean Edwards) from the dropdown