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David Kriesel: Traue keinem Scan, den du nicht selbst gefälscht hast

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  • Recommended by 4 people: 4 on Hacker News.
  • A classic. People kept recommending it from 2019 to 2022.
  • Presented by David Kriesel

Intermediate. Assumes working knowledge.

7M views11 years ago4 recommendations

SecurityGraphics and audioExploits and vulnerabilitiesWeb and application securityTesting

David Kriesel explains how Xerox scanner-copiers silently altered numbers and letters in scanned documents due to a JBIG2 compression bug.

media.ccc.de/browse/congress/2014/31c3_-_6558_-_de_-_saal_g_… Kopierer, die spontan Zahlen im Dokument verändern: Im August 2013 kam heraus, dass so gut wie alle Xerox-Scankopierer beim Scannen Zahlen und Buchstaben einfach so durch andere ersetzen. Da man solche Fehler als Benutzer so gut wie nicht sehen kann, ist der Bug extrem gefährlich und blieb lange unentdeckt: Er existiert über acht Jahre in freier Wildbahn. #DavidKriesel #6558 Help us caption & translate this video! amara.org/v/FuF3/ Introduction 2008: Verschwörungstheorien über Obamas Nationalität 2011: Veröffentlichung „Long Form Birth Certificate 2011: LFBC - Fälschungsanzeichen 24. Juli 2013: Scan von einem Bauplan 24. Juli 2013: Bauplan 24. Juli 2013: Kostenregister 24. Juli 2013: Selbstgenerierte Zahlen Wer sich auf Support verlässt, ist verlassen August: Artikel online (zweisprachig) bis 3. August: Erste Einschläge auf Techblogs August abends: Weltweit in den Techportalen August: Einschlag in Massenmedien Bildkompression: Testbild Bildkompression: Ausschnitte des Testbildes Bildkompression: GIF (hier mit 16 Farben) Bildkompression: JBig2, Text komprimiert Bildkompression: JBig2, beides komprimiert August, vormittags 3 Tage nach Einschlag: Lebenszeichen von Xerox! 6. August, nachmittags August: Humoriges August: Xerox kündigt Patch an 9. August: Nummernvertauschungen auf Defaults. August: Nummernvertauschungen in allen drei Modi August: Bug bestätigt 22. August: Patches werden released Vorherige „Lessons learned Epilog - Barack Obamas Geburtsurkunde

Why it's here

4 people recommend this

What people say. Highly recommended as a classic, entertaining, and alarming talk on how a silent software bug corrupted scanned documents for years.

snicksnakon Hacker News • Recommends

On “RC3 talk: How to survive in spacecraft [video]”

I would also highly recommend "Traue keinem Scan, den du nicht selbst gefälscht hast" 0 but I just noticed that there are no english subtitles available. 0 link to this video (2015)
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solarkrafton Hacker News • Recommends

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

(2013). The whole ordeal lead to a quite legendary presentation by David at CCC (german, no captions, live translation available but pretty bad): link to this video If you speak german and haven’t seen this yet, watch it, this is a classic. His talks are all entertaining and interesting.
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masswerkon Hacker News • Recommends

On “Enhance Speech from Adobe – Free AI filter for cleaning up spoken audio”

Epic talk (in German, David Kriesel, "Traue keinem Scan, den du nicht selbst gefälscht hast"): link to this video
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masswerkon Hacker News • Recommends

On “DARPA Is Building a $10M, Open-Source, Secure Voting System”

Thanks for the complementary links! Regarding Xerox scanner compression issues, compare this great CCC-talk by David Kriesel, "Traue keinem Scan, den du nicht selbst gefälscht hast" 0 – Sorry, German only. 0 link to this video 1 link (Didn't MS's PDF-viewer have similar issues?)
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sdoeringon Hacker News • Recommends

On “Contract by Email”

This reminded me of a great talk (in German) by David Kriesel about scanners not scanning correctly but replacing letters and numbers because of pattern matching (if I remember correctly). It was a really great talk. Not sure if there is an English version somewhere: link to this video
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a1369209993on Hacker News • Mentions

On “Contract by Email”

> Not sure if there is an English version somewhere: link to this video Seems to be: link Direct: link Which has german/english dual audio, but defaults to german (so presumably google ruined the english track on upload). If your video player doesn't support picking audio, you can probably fiddle with ffmpeg to strip out the german track.
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winReInstallon Hacker News • Mentions

On “Archiving official documents as an act of radical journalism”

Related: link to this video guy discovered that xerox workstations (like the ones to scan in government archives) corrupted numbers. Thus falsifying documents on a massive scale. Obamas "birth certificate" went through this document shredder. So distributing, non digital copies. Thats were the lasting value is.
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Log_out_on Hacker News • Mentions

On “UK plan to digitise wills and destroy paper originals "insane" say experts”

Germany scanned its national archives in with xerox stations. We will never know what numbers might have been scrambled. link to this video So similar projects existed and were so disastrous that they were quietly buried. To this day if a document was xerox scanned before the Bugfix it might be nil and void in court.
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matrsson Hacker News • Mentions

On “iPhone 16 cameras vs. traditional digital cameras”

Worse, Xerox scanners specifically meant for digitizing documents have changed text for a long time. The compression algorithm they used (I think even in the default settings) sometimes replaced e.g. 6 with 8, and similar things. See: link to this video (german, but there should be news articles from back then in english as well, somewhere)
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