5 ms·
The key is just to overwrite the pixels. Black box is the easiest. Could be any other color box if you want, or a picture of your dog, etc
by Sir_Cmpwn 9y ago
The key is just to overwrite the pixels. Black box is the easiest. Could be any other color box if you want, or a picture of your dog, etc
- walrus01 9y agountil you run into a government agency that thinks drawing a black box over something in a PDF is acceptable redaction, where the PDF is exported/published to the public in its full vector/metadata markup format, not a raster image... hilarious when you can just highlight and copy/paste to get whatever text is hidden. Have seen it several times. be careful asking non technical employees, sans training, to "just draw a black box over it", is what I'm saying.
- tedunangst 9y agoApocryphally some places have a policy that all redacted documents must be printed then rescanned before release.
- walrus01 9y agobecause fuck you, trees! right?
- simcop2387 9y agoIt's the simplest method to wipe out any metadata from the original document
- zaroth 9y agoReality Winner missed that day at NSA training!
- cesis 9y agoShe did print it and probably was caught because of that http://mashable.com/2017/06/06/printer-dots-nsa-leak.amp http://mashable.com/2017/06/06/printer-dots-nsa-leak.amp
- cperciva 9y agoDoesn't that reveal the serial numbers of the printers they use?
- joncrocks 9y agoThey just print it again and re-scan. It's printers all the way down.
- tedunangst 9y agoMaybe they don't care? Learning this was printed by the printer used for redacted info doesn't tell you much.
- TeMPOraL 9y agoThe govt should write themselves a virtual printer that would take in the data stream and output a PDF made of individual images. A typical print-to-PDF virtual printer, but government-sanctioned, and they could also make it do something like store the document in an audit database or whatever, just to give people a strong incentive not to skip it or use anything else.
- tedunangst 9y agoThat would be interesting and not hard to setup. Install cups on some box, definitely not the host containing sensitive info, and you have a limited, auditable outbound channel.
- pixl97 9y agoIt does open another risk of nation state style attacks that compromise the virtual print driver in a manner that it does not redact information, or encodes 'hidden' information into the format of the document. That seems easier to do with a digital print driver than with the messy digital to analog conversions that occur in a scanner/printer.
- Avshalom 9y agoWell if you can blur an arbitrary section you can, even if not black-black, just choose an average and write over everything with that (so adaptive grey).
- davchana 9y agoNot in US, and certainly not in any agency, but anytime I black box something in a pdf, I print it back as image to PDF printer.
- Someone 9y agoI may misinterpret what you mean by “print it back as image to PDF printer”, but I doubt that removes the text. When printing the document, the program likely will just render the text first, and the black box over it. Reason? To be able to skip rendering the text, the computer must know: - a black box will get drawn over it. - that box completely covers the text. - that box will be drawn opaquely. Verifying that isn’t easy. Save to .png is safer. It doesn’t support layers, so what you see is what you get.
- TeMPOraL 9y ago> Save to .png is safer. It doesn’t support layers, so what you see is what you get. Just make sure your document->png converter doesn't do anything silly with the alpha channel.
- Someone 9y agoIt can be worse. Apparently, Adobe’s FireWorks writes bitmap layers and vector data to .png custom data chunks.
- davchana 9y agoPDF-xChange keeps text as text if printed normally, completely selectable, vectorized, but changes and rasterises it to image if printed as image, pixelated and jpeg-ized. At about 200% zoom it is clearly visible that it is pixelated, and nothing else.