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David Kriesel: Lies, damned lies and scans

Free and Open Source Software Conference (FrOSCon) e.V.

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  • Presented by David Kriesel

Intermediate. Assumes working knowledge.

57K views11 years ago2 recommendations

Systems programmingSecurityDebuggingWeb and application security

David Kriesel explains how Xerox copiers silently altered numbers in scanned documents due to a bug in the JBIG2 compression algorithm.

media.ccc.de/browse/conferences/froscon/2015/froscon2015-152… On the scale of things too horrible to contemplate, "document-altering scanner" is right up there with "flesh-eating bacteria". Since 2006, Xerox scancopiers literally are making stuff up. They, for example, replace digits with others in scans. The replacement digits are layouted perfectly into the page, so the errors are hard to see. Sounds unbelievably insidious, but it's true. Drug prescriptions, construction plans, just anything can be affected. David Kriesel

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2 people recommend this

What people say. Recommended as a fascinating and classic talk on how a compression bug silently altered scanned documents.

bXVsbGVyon Hacker News • Recommends

On “PDF: Still unfit for human consumption, 20 years later”

> You may remember that this played a strange role in Obama's birth certificate some years back Just to clarify, the issue with the compression algorithm used by the scanner, not with the PDF format itself. There a few videos of David Kriesel explaining the bug for the curious: link to this video
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lynx23on Hacker News • Recommends

Even though this happened a long time ago, whenever I hear or think about it, I am a mazed that it didn't put Xerox out of business, or at least hurt a little more. After all, some big players were already doing digital archiving at the time. :-/ BTW, the CCC had a pretty neat presentation at that time as well: link to this video
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dorgoon Hacker News • Mentions

On “Adobe Photoshop's 'super resolution' made my jaw hit the floor”

Sounds like the next iteration of "Lies, damned lies and scans": link to this video >On the scale of things too horrible to contemplate, "document-altering scanner" is right up there with "flesh-eating bacteria". Since 2006, Xerox scancopiers literally are making stuff up. They, for example, replace digits with others in scans.
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maxnoeon Hacker News • Mentions

On “Confused Xerox copiers rewrite scanned documents, expert finds (2013)”

There is a version with an English voice over of the original talk here: link And the talk he gave in English himself here: link to this video
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Terr_on Hacker News • Mentions

On “OCR For construction documents does not work, we fixed it”

> OCR for construction documents does not work I'm reminded of the Xerox JBIG2 bug back in ~2013, where certain scan settings could silently replace numbers inside documents, and bad construction-plans were one of the cases that led to it being discovered. 0 It wasn't overt OCR per se , users weren't trying to convert pixels to characters. 0 link to this video
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