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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?
Obfuscation:
Try YUI Compressor. It's a very popular tool, built, enhanced and maintained by the Yahoo UI team.
You may also use:
Google Closure Compiler
UglifyJS
UPDATE: This question was originally asked on 2008, and The mentioned technologies are deprecated. you can use:
terser - more information in web.dev.
Private String Data:
Keeping string values private is a different concern, and obfuscation won't really be of much benefit. Of course, by packaging up your source into a garbled, minified mess, you have a light version of security through obscurity. Most of the time, it's your user who is viewing the source, and the string values on the client are intended for their use, so that sort of private string value isn't often necessary.
If you really had a value that you never wanted a user to see, you would have a couple of options. First, you could do some kind of encryption, which is decrypted at page load. That would probably be one of the most secure options, but also a lot of work which may be unnecessary. You could probably base64 encode some string values, and that would be easier.. but someone who really wanted those string values could easily decode them. Encryption is the only way to truly prevent anyone from accessing your data, and most people find that to be more security than they need.
Sidenote:
Obfuscation in Javascript has been known to cause some bugs. The obfuscators are getting a little better about it, but many outfits decide that they see enough benefit from minifying and gzipping, and the added savings of obfuscation isn't always worth the trouble. If you're trying to protect your source, maybe you'll decide that it's worth your while, just to make your code harder to read. JSMin is a good alternative.
I'm surprised no one has mentioned Google's Closure Compiler. It doesn't just minify/compress, it analyzes to find and remove unused code, and rewrites for maximum minification. It can also do type checking and will warn about syntax errors.
JQuery recently switched from YUI Compresser to Closure Compiler, and saw a "solid improvement"
Obfuscation can never really work. For anyone who really wants to get at your code, it's just a speed bump. Worse, it keeps your users from fixing bugs (and shipping the fixes back to you), and makes it harder for you to diagnose problems in the field. Its a waste of your time and money.
Talk to a lawyer about intellectual property law and what your legal options are. "Open Source" does not mean "people can read the source". Instead, Open Source is a particular licensing model granting permission to freely use and modify your code. If you don't grant such a license then people copying your code are in violation and (in most of the world) you have legal options to stop them.
The only way you can really protect your code is to not ship it. Move the important code server-side and have your public Javascript code do Ajax calls to it.
See my full answer about obfuscators here.
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.
There are a number of JavaScript obfuscation tools that are freely available; however, I think it's important to note that it is difficult to obfuscate JavaScript to the point where it cannot be reverse-engineered.
To that end, there are several options that I've used to some degree overtime:
YUI Compressor. Yahoo!'s JavaScript compressor does a good job of condensing the code that will improve its load time. There is a small level of obfuscation that works relatively well. Essentially, Compressor will change function names, remove white space, and modify local variables. This is what I use most often. This is an open-source Java-based tool.
JSMin is a tool written by Douglas Crockford that seeks to minify your JavaScript source. In Crockford's own words, "JSMin does not obfuscate, but it does uglify." It's primary goal is to minify the size of your source for faster loading in browsers.
Free JavaScript Obfuscator. This is a web-based tool that attempts to obfuscate your code by actually encoding it. I think that the trade-offs of its form of encoding (or obfuscation) could come at the cost of filesize; however, that's a matter of personal preference.
What i would do:
A. Troll the hacker!
This is will be in the second part my fake/obfuscated secret javascript code LAUNCHER.
The one you see in the source code.
What does this code?
loads the real code
sets a custom header
posts a custom variable
var ajax=function(a,b,d,c,e,f){
e=new FormData();
for(f in d){e.append(f,d[f]);};
c=new XMLHttpRequest();
c.open('POST',a);
c.setRequestHeader("Troll1","lol");
c.onload=b;
c.send(e);
};
window.onload=function(){
ajax('Troll.php',function(){
(new Function(atob(this.response)))()
},{'Troll2':'lol'});
}
B. Obfuscate the code a little
What is that?
thats the same code as above in base64
this is not the SECRET javascript code
(new Function(atob('dmFyIGFqYXg9ZnVuY3Rpb24oYSxiLGQsYyxlLGYpe2U9bmV3IEZvcm1EYXRhKCk7Zm9yKGYgaW4gZCl7ZS5hcHBlbmQoZixkW2ZdKTt9O2M9bmV3IFhNTEh0dHBSZXF1ZXN0KCk7Yy5vcGVuKCdQT1NUJyxhKTtjLnNldFJlcXVlc3RIZWFkZXIoIlRyb2xsMSIsImxvbCIpO2Mub25sb2FkPWI7Yy5zZW5kKGUpO307d2luZG93Lm9ubG9hZD1mdW5jdGlvbigpe2FqYXgoJ1Ryb2xsLnBocCcsZnVuY3Rpb24oKXsgKG5ldyBGdW5jdGlvbihhdG9iKHRoaXMucmVzcG9uc2UpKSkoKX0seydUcm9sbDInOidsb2wnfSk7fQ==')))()
C Create a hard to display php file with the real code inside
What does this php code?
Checks for the right referrer (domain/dir/code of your launcher)
Checks for the custom HEADER
Checks for the custom POST variable
If everything is ok it will show you the right code else a fake code or ban ip, close page.. whatever.
<?php
$t1=apache_request_headers();
if(base64_encode($_SERVER['HTTP_REFERER'])=='aHR0cDovL2hlcmUuaXMvbXkvbGF1bmNoZXIuaHRtbA=='&&$_POST['Troll2']=='lol'&&$t1['Troll1']='lol'){
echo 'ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChkb2N1bWVudC5jcmVhdGVFbGVtZW50KCdkaXYnKSkuaW5uZXJUZXh0PSdBd2Vzb21lJzsNCg==';//here is the SECRET javascript code
}else{
echo 'd2luZG93Lm9wZW4oJycsICdfc2VsZicsICcnKTt3aW5kb3cuY2xvc2UoKTs=';
};
?>
base64 referrer = http://here.is/my/launcher.html
SECRET javascript = document.body.appendChild(document.createElement('div')).innerText='Awesome';
FAKE = window.open('', '_self', '');window.close();
Now .. if you define event handlers in the SECRET javascript it's probably accessible.. you need to define them outside with the launchcode and pointing to a nested SECRET function.
SO... is there a easy wayto get the code?
document.body.appendChild(document.createElement('div')).innerText='Awesome';
I'm not sure if this works but i'm using chrome and checked Elements,Resources,Network,Sources,Timeline,Profiles,Audits but i didn't find the line above.
note1: if u open the Troll.php url from Inspect element->network in chrome you get the fake code.
note2: the whole code is written for modern browsers. polyfill needs alot more code.
EDIT
launcher.html
<!doctype html><html><head><meta charset="utf-8"><title></title><script src="data:application/javascript;base64,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"></script></head><body></body></html>
Troll.php
<?php $t1=apache_request_headers();if(/*base64_encode($_SERVER['HTTP_REFERER'])=='PUT THE LAUNCHER REFERER HERE'&&*/$_POST['Troll2']=='lol'&&$t1['Troll1']='lol'){echo 'ZG9jdW1lbnQuYm9keS5hcHBlbmRDaGlsZChkb2N1bWVudC5jcmVhdGVFbGVtZW50KCdkaXYnKSkuaW5uZXJUZXh0PSdBd2Vzb21lJzsNCg==';}else{echo 'd2luZG93Lm9wZW4oJycsICdfc2VsZicsICcnKTt3aW5kb3cuY2xvc2UoKTs=';}; ?>
The problem with interpreted languages, is that you send the source to get them working (unless you have a compiler to bytecode, but then again, it is quite trivial to decompile).
So, if you don't want to sacrifice performance, you can only act on variable and function names, eg. replacing them with a, b... aa, ab... or a101, a102, etc. And, of course, remove as much space/newlines as you can (that's what so called JS compressors do).
Obfuscating strings will have a performance hit, if you have to encrypt them and decrypt them in real time. Plus a JS debugger can show the final values...
Try JScrambler. I gave it a spin recently and was impressed by it.
It provides a set of templates for obfuscation with predefined settings for those who don't care much about the details and just want to get it done quickly. You can also create custom obfuscation by choosing whatever transformations/techniques you want.
Contrary to most of the other answers I suggest against YUI Compressor; you should use Google Closure.
Not much because it compresses more, but mostly because it will catch javascript errors such as a = [1,2,3,]; which make IE go haywire.
I can recommend JavaScript Utility by Patrick J. O'Neil. It can obfuscate/compact and compress and it seems to be pretty good at these. That said, I never tried integrating it in a build script of any kind.
As for obfuscating vs. minifying - I am not a big fan of the former. It makes debugging impossible (Error at line 1... "wait, there is only one line") and they always take time to unpack. But if you need to... well.
A non-open-source Javascript-based application is fairly silly. Javascript is a client-side interpreted language.. Obfuscation isn't much protection..
JS obfuscation is usually done to reduce the size of the script, rather than "protect" it. If you are in a situation where you don't want your code to be public, Javascript isn't the right language..
There are plenty of tools around, but most have the word "compressor" (or "minifier") in its name for a reason..
You can't secure client side code: just press F12 on Google Chrome, pause javascript execution and you will get all strings, even those encrypted. Beautify it and rename variables and you will get almost the original code.
If you're writing server side javascript (i.e. NodeJS) is afraid of someone hacking into your server and want to make the hacker work more difficult, giving you more time to get your access back, then use javacript compilers:
You need to use Closure Compiler on Advanced Compilation, as it's the only tool that renames all your variables, even if those are used in multiple files/modules. But it just have a problem: it only work if you write in it's coding style.
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 !
Try this tool Javascript Obfuscator
I used it on my HTML5 game not only it reduced it size from 950KB to 150 but also made the source code unreadable closure compilers and minifiers are reversable I personally dont know how to reverse this obfuscation.
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
I'm under the impression that some enterprises (e.g.: JackBe) put encrypted JavaScript code inside *.gif files, rather than JS files, as an additional measure of obfuscation.
I've been using Jasob for years and it is hands down the best obfuscator out there.
It has an advanced UI but is still intuitive and easy to use.
It will also handle HTML and CSS files.
The best way to use it is to prefix all of your private variables with something like an underscore, then use the sort feature to group them all together and check them off as targets for obfuscation.
Users can still view your source, but it's much more difficult to decipher when your private variables are converted from something like _sUserPreferredNickName to a.
The engine will automatically tally up the number of targeted variables and prioritize them to get the maximum compression.
I don't work for Jasob and I get nothing out of promoting them, just offering some friendly advice.
The downside is that it's not free and is a little pricey, but still worth it when stacked against alternatives - the 'free' options don't even come close.
Have you tried Bananascript? It produces highly compressed and completely unreadable code.
I am using Closure-Compiler utility for the java-script obfuscation. It minifies the code and has more options for obfuscation.
This utility is available at Google code at below URL:
Closure Tools
But now a days I am hearing much of UglifyJS. You can find various comparison between Closure Compiler and UglifyJS in which Uglify seems to be a winner.
UglifyJS: A Fast New JavaScript Compressor For Node.js That’s On Par With Closure
Soon I would give chance to UglifyJS.
As a JavaScript/HTML/CSS obfuscator/compressor you can also try Patu Digua.
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.
I've used this in the past, and it does a good job. It's not free, but you should definitely take a look.
JavaScript Obfuscator & Encoder
After some security concerns about user plugins running spyware, I'm looking for a way to disable all JavaScript before and after my site's JS. Ideas?
Is there a way to unset all native JavaScript, or block plugins from modifying a site's code with JavaScript? This is a huge security threat and I'm hoping it's easily remedied.
EDIT: I'm referring to browser add-ons. Basically, any JavaScript code that I didn't write myself and put on my site.
Is there a way to unset all native JavaScript, or block plugins from modifying a site's code with JavaScript?
No.
This is a huge security threat and I'm hoping it's easily remedied.
It is, yes: get your users to stop installing spyware.
Look, even if the spyware isn’t able to use an add-on to modify your site, there are any number of other possibilities for mucking about at a level above the browser. You can’t fix a fundamentally unsafe computer from the web side.
The solution that I found that was effective against the spyware in question was putting some garbage JavaScript below the JavaScript on my site. Here's an example:
(function() {
....
});
thisIsGibberish
This sort of solution can be countered easily with placing a semi-colon in front of any code, but this was the kind of thinking I was trying to inspire.
Can someone tell me which tools/methods you use to obfuscate the javascript code when you create your addon/s?
We have a problem of another DEV messing with our code, creating some other crap with it and then bad mouthing us :(
(seriously, how low can some people stoop?)
I understand it wont keep truly determined souls at bay, but we want to atleast make him work for it before he gets the source. Frustrate the bugger for a while at least ;)
Thanks!
If you want to publish your addon in addons.mozilla.org I think that you must not use obfuscated javascript.
You can try to contact someone from Mozilla about your problem and if the problem is really serious they can blacklist the other add-on.
Here are some links you may find useful:
http://www.javascriptobfuscator.com
http://javascriptcompressor.com/
http://www.java2s.com/Code/JavaScriptDemo/UnescapeEncoderDecode.htm
http://jscompress.com/
http://scriptasylum.com/tutorials/encode-decode.html
But you know, one click encrypt = one click decrypt :(
I'm not well versed in Firefox-specific JavaScript, but it should be possible to run it through a JavaScript minifier like http://jscompress.com/ to obfuscate your code.
Is there some way to make Firebug not work at all on a website?
If the performance of your website suffers when Firebug is enabled, you may want to display a warning, asking users to switch it off. You can easily detect if Firebug is enabled through JavaScript.
WARNING: EXTREME EVIL. NEVER EVER USE THIS CODE. Also, it won't deter someone who is resourceful.
setTimeout(checkForFirebug, 100);
function checkForFirebug()
{
if (window.console && window.console.firebug) {
while(true); //Firebug is enabled
}
setTimeout(checkForFirebug, 100);
}
EDIT: I figured I would provide an answer to the real question behind the question. The fact is, Javascript is an interpreted language and that interpreter is in the browser. This makes it literally impossible to provide Javascript that is both secure and runnable. The same goes for HTML and CSS. The best you can do is minify the Javascript to make it a little less easy to reuse. If the company in question really wants "secure" Javascript, you just have to tell them it's not truly possible.
Ummm....
What does using Firefox (with or without Firebug) have to do with this?
I use IE and I can just as easily view your JavaScript. Likewise with Google Chrome. Hell, I can download your JavaScript when viewing your webpage on my Palm Treo.
Anything which can be accessed directly from a browser can be downloaded and analyzed at leisure. As others have said (better than I), JavaScript which runs on your website should be considered to be "open source". Find another way to do it (i.e. processing on your server) or accept that someone will hack in and look at it.
Mind you, are your routines so obviously good (in terms of what they do to your webpages) that a user will go to your website and immediately say "Hey, this is cool, I wonder how they do it?" If not, don't worry about it - most people won't be interested enough to try to look at your JavaScript.
You could try minifying your JavaScript, but that's not 100% going to stop someone who's determined. You could try encrypting it, but I've never tried. Or put a copyright notice in your JavaScript files, so at least someone else won't be able to subsequently pass off your work as yours without getting into legal trouble.
No. Nobody wants your javascript routines anyway. :-)
And if you're worried about unsecure code, you should rewrite your site to be secure instead of trying to hide its problems.
If you want to hide your HTML/CSS/JavaScript from visitors, that is not possible. Even if one cannot use Firebug, one can simply view the HTML source code. Any external JavaScripts and stylesheets can be downloaded as the plain text files they are. Because HTML, CSS, and JavaScript are client-side technologies, that are downloaded as plain text and interpreted by the web browser, it is theoretically impossible to hide your code. The best thing you can do to make the code harder to understand, is to obfuscate it. See Wikipedia.
You could click on the Off button to disable it.
Or are you trying to prevent your users from running it? If so, good luck...
"My javascript routines" belong to the company I work for and my company wants the stuff we develop secured.
You do not secure stuff by lightly patting "hackers" on the fingers when they use one specific debugging tool. Try to prevent them from using the ultimate hacker tool: "View Source".
If it's out there it's out there. "Secure" means something different in this context. It means securing whatever important data you have by employing techniques that are impenetrable* even with full knowledge of the source code. The source code itself is not securable, and neither does it need to be.
*) "impenetrable" = difficult enough to subvert in a reasonable amount of time, nothing is 100% :)
You could develop your site in Flash, Silverlight, or Java. Firebug will then be limited to displaying your base HTML.
I'm assuming you're worried about reverse engineering with FireBug.
Anything you send to the client, all your javascript, is open to whoever you send it to. Don't have anything there that you don't want people to see. There is no way to prevent someone else's browser from using Firebug, or a lot of other tools, to analyze your code. You could try to make your html, css, and javascript really bad, and that might slow them down! There are obfuscation programs to make it difficult to read. If you want to hide functionality, you'll need to have it happen on the server.
No, of course not. If Firebug is revealing something that you must prevent your users from seeing, then you are approaching this problem completely wrong. I am not trying to be rude or degrading, but attempting to block one particular program in an effort to fix a bug in your web application is about as logical as a bucket of steam. Firebug does nothing magical; I can do anything it does by writing some code. Having said that, there must be an underlying issue that you should be more concerned about.
Just to provide a little trick that i use helps lower people seeing your code,
One of the tricks i do that does not prevent the JavaScript from being found by the experianced developer or hacker, but deters the few people playing with Firebug / inspector,
use jQuery or another lib with a grate selector
the second port of call is all you files put them into a loader file E.G
Loader.js
(function($){
function loader(type, addr){
var head = $("head")[0];
switch(type){
case "script":{
var element = $(document.createElement("script"));
element.attr("type", "text/javascript");
element.attr("src", addr);
element.attr("loaded", "loader")
$(head).append(element);
}
case "style":{
var element = $(document.createElement("link"));
element.attr("rel", "stylesheet");
element.attr("type", "text/css");
element.attr("loaded", "loader");
element.attr("href", addr);
$(head).append(element);
}
}
}
loader("css", "path/to/your.css");
loader("script", "path/to/script.js");
loader("script", "unloader.js")
})(jQuery);
So to start with were using a closure this prevent anyone from using the console input of the inspector to see the code that has been run.
so once this file has been passed it will load your CSS and JS but you can still see there loaded in the head element of your inspector, thanks to browsers and the they way they work you can remove and not unload them this means the code will not be removed from execution but will prevent them being shown in the inspector this is what goes in the unloader.
unloader.js
(function($){
$("head *[loaded=loader]").remove();
})(jQuery);
The above will remove the the files loaded though the loader.
The only thing you need to remember is to add loaded="loader" to your scrip that that includes the loader, now this does not make it impossible for some one to see your files but stops the inspector from showing them in the HTML,
the ways around this can be to "View Source" code see the loader file and read that so make sure you minimize the code i use Google Closure Compiler (http://closure-compiler.appspot.com/home)
even this does not stop them it just make it more difficult. one of the steps i have tested but dont use is on the loader and files your loading use a .HTAccess rule to check that they have a reffer link form your site this will prevent them browsing directly to your js/css code files
another tip don't store them in normal places and don't use common names E.G scripts in /scripts/ CSS in /style/ or style.css
Here is an example of the loader Closure Compiled then Obfuscated
Loader.js
var _0xc596=["\x68\x65\x61\x64","\x73\x63\x72\x69\x70\x74","\x63\x72\x65\x61\x74\x65\x45\x6C\x65\x6D\x65\x6E\x74","\x74\x79\x70\x65","\x74\x65\x78\x74\x2F\x6A\x61\x76\x61\x73\x63\x72\x69\x70\x74","\x61\x74\x74\x72","\x73\x72\x63","\x6C\x6F\x61\x64\x65\x64","\x6C\x6F\x61\x64\x65\x72","\x61\x70\x70\x65\x6E\x64","\x6C\x69\x6E\x6B","\x72\x65\x6C","\x73\x74\x79\x6C\x65\x73\x68\x65\x65\x74","\x74\x65\x78\x74\x2F\x63\x73\x73","\x68\x72\x65\x66","\x73\x74\x79\x6C\x65","\x63\x73\x73","\x70\x61\x74\x68\x2F\x74\x6F\x2F\x79\x6F\x75\x72\x2E\x63\x73\x73","\x70\x61\x74\x68\x2F\x74\x6F\x2F\x73\x63\x72\x69\x70\x74\x2E\x6A\x73","\x75\x6E\x6C\x6F\x61\x64\x65\x72\x2E\x6A\x73"];(function (_0x76e5x1){function _0x76e5x2(_0x76e5x2,_0x76e5x3){var _0x76e5x4=_0x76e5x1(_0xc596[0])[0];switch(_0x76e5x2){case _0xc596[1]:var _0x76e5x5=_0x76e5x1(document[_0xc596[2]](_0xc596[1]));_0x76e5x5[_0xc596[5]](_0xc596[3],_0xc596[4]);_0x76e5x5[_0xc596[5]](_0xc596[6],_0x76e5x3);_0x76e5x5[_0xc596[5]](_0xc596[7],_0xc596[8]);_0x76e5x1(_0x76e5x4)[_0xc596[9]](_0x76e5x5);;case _0xc596[15]:_0x76e5x5=_0x76e5x1(document[_0xc596[2]](_0xc596[10]));_0x76e5x5[_0xc596[5]](_0xc596[11],_0xc596[12]);_0x76e5x5[_0xc596[5]](_0xc596[3],_0xc596[13]);_0x76e5x5[_0xc596[5]](_0xc596[7],_0xc596[8]);_0x76e5x5[_0xc596[5]](_0xc596[14],_0x76e5x3);_0x76e5x1(_0x76e5x4)[_0xc596[9]](_0x76e5x5);;} ;} ;_0x76e5x2(_0xc596[16],_0xc596[17]);_0x76e5x2(_0xc596[1],_0xc596[18]);_0x76e5x2(_0xc596[1],_0xc596[19]);} )(jQuery);
unloader.js
var _0xc2fb=["\x72\x65\x6D\x6F\x76\x65","\x68\x65\x61\x64\x20\x2A\x5B\x6C\x6F\x61\x64\x65\x64\x3D\x6C\x6F\x61\x64\x65\x72\x5D"];(function (_0x3db3x1){_0x3db3x1(_0xc2fb[1])[_0xc2fb[0]]();} )(jQuery);
to reproduce of to: http://closure-compiler.appspot.com/home put your code in under the // ADD YOUR CODE HERE
Then the result that is given back use: http://www.javascriptobfuscator.com/Default.aspx to make it even more unreadable.
Hope this helps any one else looking to make the JS as Secure as possible
But please remember as every one else has said this will not stop the pro hackers just make it very difficult to read and understand
No...............
Ultimately, no, as the browser (in this case firefox) on their machine can choose to run whatever javascript (such as firebug) it wants to. You cannot prevent users from running it along with your website.
if you want to protect your code, you could try encrypting your javascript source code
google encrypt javascript source
My reputation is too low to comment, but I just wanted to point out something that I noticed after learning about window.history.pushState(); it seems that you can change what is currently in the address bar, and once you do that, "view page source" doesn't work. So if there was a way to block developer tools from working, I wouldn't know how to view the source code.
EDIT: After using window.history.pushState(), when I view developer tools, it tells me to reload the page to view what is in a javascript file (but then again it does show the address to the JS file so that doesn't help much)
I'm working on building a development tool that is written in JavaScript.
This will not be an open source project and will be sold (hopefully) as a commercial product.
I'm looking for the best way to protect my investment. Is using an obfuscator (code mangler) enough to reasonably secure the code?
Are there other alternatives that I am not aware of?
(I'm not sure if obfuscator is the right word, it's one of the apps that takes your code and makes it very unreadable.)
I'm going to tell you a secret. Once you understand it, you'll feel a lot better about the fact that Javascript obfuscation is only really useful for saving bandwidth when sending scripts over the wire.
Your source-code is not worth stealing.
I know this comes as a shock to the ego, but I can say this confidently without ever having seen a line of code you've written because outside the very few realms of development where serious magic happens, it's true of all source-code.
Say, tomorrow, someone dumped a pile of DVDs on your doorstep containing the source code for Windows Vista. What would you be able to do with it? Sure, you could compile it and give away copies, but that's just one step more effort than copying the retail version. You could painstakingly find and remove the license-checking code, but that's something some bright kid has already done to the binaries. Replace the logo and graphics, pretend you wrote it yourself and market it as "Vicrosoft Mista"? You'll get caught.
You could spend an enormous amount of time reading the code, trying to understand it and truly "stealing the intellectual property" that Microsoft invested in developing the product. But you'd be disappointed. You'd find the code was a long series of mundane decisions, made one after the other. Some would be smarter than you could think of. Some would leave you shaking your head wondering what kind of monkeys they're hiring over there. Most would just make you shrug and say "yeah, that's how you do that."
In the process you'll learn a lot about writing operating systems, but that's not going to hurt Microsoft.
Replace "Vista" with "Leopard" and the above paragraphs don't change one bit. It's not Microsoft, it's software. Half the people on this site could probably develop a Stack Overflow clone, with or without looking at the source of this site. They just haven't. The source-code of Firefox and WebKit are out there for anyone to read. Now go write your own browser from scratch. See you in a few years.
Software development is an investment of time. It's utter hubris to imagine that what you're doing is so special that nobody could clone it without looking at your source, or even that it would make their job that much easier without an actionable (and easily detectable) amount of cut and paste.
I deeply disagree with most answers above.
It's true that every software can be stolen despite of obfuscation but, at least, it makes harder to extract and reuse individual parts of the software and that is the point.
Maybe it's cheaper and less risky to use an obfuscation than leaving the code open and fighting at court after somebody stole the best parts of our software and made dangerous concurrency.
Unobfuscated code whispers:
Come on, analyze me, reuse me. Maybe you could make a better software using me.
Obfuscated code says:
Go away dude. It's cheaper to use your own ideas than trying to crack me.
You are going to be fighting a losing battle if you try to obfuscate your code in the hopes of someone not stealing it. You may stop the casual browser from getting at it, but someone dedicated would almost certainly be able to overcome any measure you use.
In the past I have seen people do several things:
Paste a lot of whitespace at the top of the page with a message telling people that the code is unavailable, when in actuality you just need to scroll down a few pages to get at it.
Running it through an encoder of some kind, this is so so useful as it can just be run through the decoder.
Another method is to reduce variable names to one character and remove whitespace (this is also an efficiency thing).
There are many other methods.
In the end, your efforts are only likely to stop the casual browser from seeing your stuff. If someone dedicated comes along then there is not much you will be able to do. You will have to live with this.
My advice would be to make a really awesome product that attracts the most people and beat off any competition by having the best product/service/community and not the most obfuscated code.
You're always faced with the fact that any user that comes to your webpage will download some working version of your Javascript source. They will have the source code. Obfuscating it may make it very difficult to be reused by someone with the intent to steal your hard work. However, in many cases someone can even reuse the obfuscated source! Or in the worst case they can unravel it by hand and eventually comprehend it.
An example of a situation like yours might be Google Maps. The Javascript source is clearly obfuscated. However, for really private/sensitive logic they push the data to the server and have the server process that information using XMLHttpRequests (AJAX). With this design you have the important parts on the server side, much more tightly controlled.
That's probably about the best you can do. Just be aware that anybody with enough dedication, can probably de-obfuscate your program. Just make sure you're comfortable with that before embarking on your project. I think the biggest problem with this would be to control who's using it on their site. If somebody goes to a site with your code on it, and likes what it does, it doesn't matter that they don't understand what the code does, or can't read it, when they can just copy the code, and use it on their own site.
A obfuscator won't help you at all if someone wants to figure out the code. The code still exists on the client machine and they can grab a copy of it and study it at their leisure.
There is simply no way to hide code written in Javascript since the source code has to be handed to the browser for execution.
If you want to hide your code, you have the following options:
1) Use an environment where compiled code (not source) is downloaded to the client, e.g. Flash or Silverlight. I'm not even sure that's foolproof, but it's certainly much better than Javascript.
2) Have a back end on the server side that does the work and a thin client that just makes requests to the server.
I'd say yes, it's enough if you also make sure than you compress the code as well using a tool like Dean Edward's Packer or similar. If you think about what is possible with tools like .NET Reflector in terms of reverse engineering compiled code / IL in .NET, you realize that there's nothing you can do to completely protect your investment.
On the other hand, remember that folks who release their source code also seem to make do quite nicely anyway - it's their experience that people want more than their intellectual property.
code obfuscator is enough for something that needs minimal protection, but I think it will definitely not enough to really protect you. if you are patient you can realy de-mangle the whole thing.. and i'm sure there are programs to do it for you.
That being said, you can't stop anyone from pirating your stuff because they'll eventually will break any kind of protection you create anyway. and it is espcially easy in scripted language where the code is not compiled.
If you are using some other language, maybe java or .NET, You can try doing things like "calling home" to verify that a license number matches a given url. Which works if you your app is some sort of online app that is going to be connected online all the time. But having access to the source, people can easily bypass that part.
In short, javascript is a poor choice for what you are doing.
A step up from what you are doing is maybe using a webservice backend to get your data. Let the webservice handle the authentication/verification process. Requires a bit of work to make sure it is bulletproof, but it might work
If this is for a website, which by its very nature puts viewing of its code one menu click away, is there really any reason to hide anything? If someone wants to steal your code they will most likely go through the effort of making even the most mangled code human readable. Look at commercial websites, they don't obfuscate their code, and no one goes out and steals code from the google apps. If you are really worried about code theft, I would argue for writing it in some other compiled language. (which does of course destroy the whole webapp thing...) Even then, you aren't totally safe, there are many de-compilers out there.
So really, there is no way to do what you want in the face of anyone with sufficient motivation.