Lock beamed documents?

March 23, 2007 5:41 PM

If I beam to you a document or spreadsheet from my pocket computer, is there a way for me to secure the file to prevent you from sharing it by beaming it to others?
posted by Shalerman to computers & internet (7 comments total)

Password protect it?
posted by Solomon at 6:04 PM on March 23, 2007

No. You can't control anything about my machine. Even if you think there's some low-level "rights management" way that my machine really doesn't do what I want it to, there will always be the "brain in a jar" problem.

If I can see it, I can copy it.

If this is confusing to you, think about the simplest case--I have a Polaroid instant camera handy and I take a snapshot of your s3cr1t.
posted by cmiller at 6:26 PM on March 23, 2007

cmiler is right. Document control of this kind is basically impossible, even if MS Office would tempt you to think otherwise.
posted by unSane at 6:30 PM on March 23, 2007

In addition to what cmiller says, if you're on a PalmOS, I believe there is a bit that can be set that says "This file cannot be beamed." While this would stop a novice from sending a file, it is trivially easy for the other person to flip the bit themselves. Additionally, if the device is hotsync'd with a PC, then it will be copied to that computer.
posted by i love cheese at 7:15 PM on March 23, 2007

cmiller is right and wrong. There is always someone who can break your electronic security, just as there is someone who can break your physical security. There are solutions that may be good enough for you, depending on your particular requirements.

You need to assess (1) the value of your proprietary information and (2) the degree of effort you are willing to invest.

At one end of the spectrum, there are unencumbered files. Anyone can and will take these. At the other end of the specturm is a physically secure room with the person who needs to see this document, a device, and an armed guard. The armed guard is authorized to shoot the person if he pulls out his polaroid camera.

Between the two extremes are many intermediate points. There are a wide array of DRM techniques you can choose to employ, there are legal means you can use, interpersonal trust, physical measures and more.

The solution that will work for you depends upon how secure you need your document to be, and how much effort you are willing to expend to achieve this.
posted by b1tr0t at 9:58 PM on March 23, 2007

In addition to the points already made by b1tr0t and cmiller, I think it's also important to consider the "pain in the ass factor": when you start employing fancy technical measures to discourage people from doing things, they often cause unintended problems. (Hypothetical example: suppose you find some way of making files you send to someone 'unbeamable,' and a few weeks later the guy gets a new/upgraded device and tries to move his files over by beaming them, only to find that the files from you won't beam. He's not trying to screw you, but you've just ruined his day anyway.)

Since a dedicated person is always going to be able to copy your content once you give it to them, and a truly honest person isn't going to copy it even if it's unprotected, you need to very carefully weigh the risks against the rewards of trying to enforce this via software.

To be frank, I think that using technical "don't copy" or "don't print" measures, particularly the crummy ones in most consumer software, are rarely more useful than 'social protection' (asking nicely, advising them of copyright law, threatening to sic your lawyers on them, etc.).
posted by Kadin2048 at 11:23 PM on March 23, 2007

The level of security for the file would be at the low end of the spectrum. Those who would receive the beamed file cannot sync their device with a computer, the users of the devices are, for the most part, at a novice level.
Knowing this, is it possible to "flip a bit", tag, or set off the tazer function (kidding) to prevent the document from being sent on to another? Pain in the ass function is not required.
thanks
posted by Shalerman at 6:40 AM on March 24, 2007