Thanks Juan that's exactly what I was looking for! On Mon, Jun 30, 2008 at 2:31 PM, Juan Pablo Califano < [EMAIL PROTECTED]> wrote:
> Hi, > > The byte manipulation is possible and not too hard if you're using AS 3.0. > Basically, you can load any file and specify the dataFormat as binary. You > can then access the raw content of the file as a ByteArray. With it, you > can > do pretty much any manipulation you need. Once you have "reconstructed" > your > swf, just use a regular Loader, but instead of calling the load() method, > call loadBytes() and pass the ByteArray. > > I've done that once, in a similar situation . We were required that a swf > file was not "playable" by itself; I didn't have to be "really" > encripted with some strong algorithm -- which would be overkill for medium > to big files anyway. So we just did some basic XOR ciphering, using a mask > (a 128 bit GUID). Basically, each byte in the input was xored with a > byte from the mask; after xoring, both positions were advanced one byte; > when the end of the mask was reached, the position was reset to 0; just > repeteat to EOF and that's it. > > Hope it helps. > > Cheers > Juan Pablo Califano > > > 2008/6/30, Stuart Campbell <[EMAIL PROTECTED]>: > > > > > > > > > I don't think that Adobe is especially interested in promoting > > > FlashPaper, > > > > which is essentially a competitor or substitute for PDF. > > > > > > > Pity about FP being deprecated. However, this is a > use-once-then-throw-away > > project so I'm not too worried about the technology not being supported > in > > future. > > > > You should make it very clear to your client, in writing, that all you > can > > > do is make it more difficult. Otherwise, you may be on the wrong end of > a > > > lawsuit when one of these documents does eventually get emailed around. > > > > > > > Yes, you make a good point. Will definitely make this clear in writing. > > > > > > > How do you know you've successfully used HTTP headers to do this? Since > > all > > > the action is on the client, how exactly can you verify that this has > > been > > > successful? > > > > > > > What I mean is that we have tested it in various browsers etc. I realise > > that this is merely induction and that I can't know that it will always > > work > > on every client in every context. However, we are not really relying on > > this. What we need to do is also have some kind of crude scrambling of > the > > document swf that can be unscrambled by a wrapper swf. That way, even if > > the > > doc was in the cache it wouldn't be readable by a browser. *However, I'm > > assuming you can manipulate the bytes of an swf in the Flash > > player.*(Disclosure: I am not a Flash developer I'm a C# guy - but I'm > > going to be > > hacking away at AS as though my life depended on it). > > > > There are third-party products that manipulate HTTP request and response > > > headers as a matter of course. Some of these are common consumer > > > applications. Some of these are installed by computer manufacturers. > > > > > What about the tech-savvy business person who asks his coworker in IT > down > > > the hall to grab a copy? > > > > > > > You're right. Anyone could intercept the requests for the document. > > However, > > given the crude scrambling approach it would be only be usable after some > > determined hacking. And if they did that then they could never claim they > > did it by accident, which I think that is all we are trying to guard > > against > > - We are just trying to make it difficult to do - not impossible. After > > all, > > all consumers have signed Non Disclosure Agreements. > > > > If you're interested in a more secure solution for this, you might want > to > > > take a look at Adobe LiveCycle ES Rights Management. This will let you > > > deliver PDFs that can only be used in very specific ways, by authorized > > > users, using Adobe Acrobat or Adobe Reader only (no third-party PDF > > > viewers). It's fairly expensive, but will let you make it much more > > > difficult than any of the solutions you're considering. > > > > > > > Thanks for pointing out LiveCycle, Dave. I looked into it and it seems > very > > comprehensive. There are a couple of reasons why I can't use it though. > > Most > > of the users work at institutions with locked-down desktop deployments. > > They > > can't install *anything* - even a browser plug-in (hence my choice of the > > ubiquitous flash plugin). And some of these companies have deployed 3rd > > party PDF readers, which is pretty much a non-starter for LiveCycle. > > Additionally, LiveCycle is a mammoth toolset and I'm not sure I could get > > my > > head around it, develop the solution, deploy it, and go-live by this > Friday > > (which is my scary deadline!). I will consider LiveCycle for a future > > project though. > > > > Anyway, thanks very much for your input. I'd be very interested to know > if > > you think the swf byte manipulation thing is doable. > > > > TIA > > > > Stu > > _______________________________________________ > > Flashcoders mailing list > > [email protected] > > http://chattyfig.figleaf.com/mailman/listinfo/flashcoders > > > _______________________________________________ > Flashcoders mailing list > [email protected] > http://chattyfig.figleaf.com/mailman/listinfo/flashcoders > _______________________________________________ Flashcoders mailing list [email protected] http://chattyfig.figleaf.com/mailman/listinfo/flashcoders
