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Another reminder that it's not as easy to get rid of information as you think
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jducoeur
The tech-business amusement going around the blogosphere today is that Facebook's long-secret company valuation got accidentally revealed. (Thanks to TechCrunch.) The actual valuation isn't all that surprising ($3.7 billion, which is in line with most good guesses), but how it came out was a good illustration of tech-risk.

You see, they've been engaged in a lawsuit for years now, over who actually created the technology. As part of that, the court unsealed some proceedings recently, with broad sections redacted, and published that as a PDF. (The article above links to it.) But if you simply copy the redacted sections (which show as blank white in the PDF) into, say, Notepad, you get to read the original contents.

In other words, *somebody* applied physical-world thinking to the technology: they essentially covered over the secret bits with white-out. (In practice, I suspect they changed the color of the relevant text to the same white as the background.) Which kinda makes sense if you think this is a piece of paper, but none at all if you understand what's going on here -- it's just tweaking a flag about the information. But the old information is still there: even if the copy-and-paste trick didn't work, it would be fairly easy to just read the source of the PDF to find the "hidden" information.

(A number of people are apparently jumping up and down, claiming that this is a bug in the PDF format, but I suspect that's nonsense: the PDF is probably doing exactly what it was told to do, which is to print this text in white.)

Moral of the story is, if you really care about keeping secrets online, it is important to understand what the heck you're doing. Solutions that work in the real world can be comic failures in electronic media...



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We have big huge documentation about how you can't just cover up text in PDFs and not have them be visible. You can cover them up, print them, and re-pdf them and that will work, but you can't submit it with the cover ups as is....

Someone needs to go shout at their lit tech department. The firms involved are *not* small ones.

Yep. (Reminds me of the California case where someone put all kinds of documents up on the web, gave them regular designations, and simply didn't provide links to the sensitive ones, thinking that this would be sufficient security.)

This is hardly news. At least once a year somebody "hacks" a "redacted" pdf and publishes it's "secrets." Given how much publicity it always garners, I am in turn astounded roughly once a year that the only way to redact a document is with a black marker pen and a photocopier.

That's... ridiculous. *shakes head*

Ha! An excellent demonstration of the second rule of WYSIWYG: if you don't see it, that doesn't mean it isn't there. (the first rule clearly being that what you see is only a gross approximation of what it will look like to other people)

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