Question

I’m working on an Windows application(created in .NET) which one of its functions is to play local FLVs using SWF components.

Now I need to create an encryption application to make sure those FLVs cannot be played freely, only the SWF player will know how to decrypt that file(using a key received from .NET app).

I was thinking of creating an Air app to encode my flvs (maybe ByteArray class?), using some algorithm to shuffle/unshuffle characters based in a key string.

My main need is how to encode/decode a file using Air/Flash.
I tried some times, just trying to load a FLV, convert to ByteArray, then save the new FLV, but this new FLV won’t play. Opening into Notepad++, I noticed the file have a few characters before it’s FLV header.

Anyone knows how to do that correctly? Thanks!

Answer 1

Here is a example of what I achieved throught my experiences and googling. Works perfectly.

    public function Main():void 
    {           
        us.load(new URLRequest("file.ext"))
        us.addEventListener(Event.COMPLETE, onVideoLoaded);
    } 

    private function onVideoLoaded(e:Event):void
    {
        var bytes:ByteArray = new ByteArray();  
        us.readBytes(bytes, bytes.length, us.bytesAvailable);

        bytes = encrypt(bytes);         
        saveFile(bytes);
    }

    private function saveFile(bytes:ByteArray):void
    {           
        var fileStream:FileStream = new FileStream();
        fileStream.open(File.desktopDirectory.resolvePath("filename.ext"), FileMode.WRITE);
        fileStream.writeBytes(bytes, 0, bytes.length);
        fileStream.close();

        fileStream.addEventListener(OutputProgressEvent.OUTPUT_PROGRESS, onCompleteFile);
    }


    private function encrypt(bytes:ByteArray):ByteArray 
    {
        var i:int = bytes.length;
        while (i--)
        {
            bytes[i] += 128;
        }

        return bytes;
    }

Using ROT128 to encrypt a file, more info here.