SWF Obfuscator

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lines:103
license : see code comments
modified : 2010-02-10 03:09:03

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<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
<mx:Script>
<![CDATA[
	import flash.events.Event;
	import flash.net.FileFilter;
	import flash.net.FileReference;
	import flash.utils.ByteArray;
	import mx.controls.Alert;

private function sampleDefinitionsList ():void {
		// you cannot obtain definitions list without actually parsing swf :(
		// for simple way to do it, see http://etcs.ru/blog/as3/getdefinitionnames/
		taList.text = "_transform\rAbstractRenderSession\raway3d.core\rView3D";
	}

private function obfuscate ():void {
		Alert.show ("In following dialog, select SWF file to obfuscate.", "Information", 0x4, null, loadFile);
	}

private function loadFile (e:Event):void {
		ref = new FileReference;
		ref.addEventListener (Event.SELECT, swfSelected);
		ref.browse ([new FileFilter("SWF Files", "*.swf")]);
	}

private function swfSelected (e:Event):void {
		ref.addEventListener (Event.COMPLETE, swfLoaded);
		ref.load ();
	}

private function swfLoaded (e:Event):void {
		// place uncompressed swf in byte array
		if (ref.data.readMultiByte (3, "us-ascii") == "CWS") {
			swf = decompress (ref.data);
		} else {
			swf = ref.data;
		}

// sort definitions list by length for long defs to be processed 1st
		var defs:Array = taList.text.split ("\r");
		defs.sort (function (a:String, b:String):int {
			var aL:int = a.length, bL:int = b.length; if (aL < bL) return 1; else if (aL > bL) return -1; return 0;
		});

// generate random translation
		var i:int, poops:Array = [];
		for (i = 0; i < defs.length; i++) {
			var s:String = "";
			while ((s == "") || (poops.indexOf (s) > -1)) s = randomString (defs [i].length);
			poops [i] = s;
		}

// obfuscate
		while (defs.length > 0) {
			var def:String = defs.shift ();
			var poop:String = poops.shift ();
			swf.position = 0;
			while (findString (swf, def)) for (i = 0; i < poop.length; i++) swf.writeByte (poop.charCodeAt (i));
		}

Alert.show ("In following dialog, select where to save obfuscated SWF file.", "Information", 0x4, null, saveFile);
	}

private function saveFile (e:Event):void {
		new FileReference().save (compress (swf));
	}

private var ref:FileReference;
	private var swf:ByteArray;

private function randomString (length:int):String {
		var s:String = "";
		while (s.length < length) s += String.fromCharCode (33 + int (32 * Math.random ()));
		return s;
	}

private function findString (data:ByteArray, string:String):Boolean {
		var i:int = 0;
		while (data.bytesAvailable) {
			var char:int = data.readByte ();
			if (char == string.charCodeAt (i)) {
				i++; if (i == string.length) {
					// we found match
					data.position -= string.length; return true;
				}
			} else {
				i = 0;
			}
		}
		return false;
	}

// compression functions by Nikita Leshenko
	// http://active.tutsplus.com/tutorials/workflow/protect-your-flash-files-from-decompilers-by-using-encryption/

private function compress (data:ByteArray):ByteArray {
		var header:ByteArray = new ByteArray;
		var decompressed:ByteArray = new ByteArray;
		var compressed:ByteArray = new ByteArray;

header.writeBytes (data, 3, 5); // read the header, excluding the signature
		decompressed.writeBytes (data, 8); // read the rest

decompressed.compress ();

compressed.writeMultiByte ("CWS", "us-ascii"); // mark as compressed
		compressed.writeBytes (header);
		compressed.writeBytes (decompressed);

return compressed;
	}

private function decompress (data:ByteArray):ByteArray {
		var header:ByteArray = new ByteArray;
		var compressed:ByteArray = new ByteArray;
		var decompressed:ByteArray = new ByteArray;

header.writeBytes (data, 3, 5); // read the uncompressed header, excluding the signature
		compressed.writeBytes (data, 8); // read the rest, compressed

compressed.uncompress ();

decompressed.writeMultiByte ("FWS", "us-ascii"); // mark as uncompressed
		decompressed.writeBytes (header); // write the header back
		decompressed.writeBytes (compressed); // write the now uncompressed content

return decompressed;
	}

]]>
</mx:Script>
<mx:Button width="400" label="Load and obfuscate SWF" click="obfuscate()"/>
<mx:Label text="Please edit the list of definitions to be obfuscated in the text area below"/>
<mx:TextArea id="taList" width="400" height="350" initialize="sampleDefinitionsList()" />
</mx:Application>

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