7.1M views · Jan 1, 2015 · 1:03:40 · 4 HN recommenders · 9 mentions · discussed 2019–2025
David Kriesel's 31C3 talk, in German, on the discovery that Xerox scanner-copiers silently replace digits and letters in scanned documents. He explains how the bug stayed unnoticed in the wild for years.
Why Hacker News points people here: Called a classic CCC talk, and the Xerox bug is cited as a cautionary tale about trusting scans and digitized archives.
“If you speak german and haven’t seen this yet, watch it, this is a classic.”HN comment, 2021
“I would also highly recommend”
German talk on scanners silently altering documents.
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] this video (2015)
“If you speak german and haven’t seen this yet, watch it, this is a classic.”
Legendary CCC presentation on the Xerox scanner number-changing bug.
(2013). The whole ordeal lead to a quite legendary presentation by David at CCC (german, no captions, live translation available but pretty bad): 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.
“Epic talk (in German, David Kriesel,”
German talk about not trusting scans.
Epic talk (in German, David Kriesel, "Traue keinem Scan, den du nicht selbst gefälscht hast"): this video
“compare this great CCC-talk by David Kriesel”
CCC talk on Xerox scanner compression altering scanned content (German).
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] this video [1] link (Didn't MS's PDF-viewer have similar issues?)
“It was a really great talk.”
German talk on scanners replacing digits through pattern matching.
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: this video
“Which has german/english dual audio, but defaults to german”
> Not sure if there is an English version somewhere: 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.
“guy discovered that xerox workstations (like the ones to scan in government archives) corrupted numbers.”
Xerox scanners corrupted numbers in scanned archives.
Related: 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.
“We will never know what numbers might have been scrambled.”
Xerox scan bug as cautionary tale for digitizing archives.
Germany scanned its national archives in with xerox stations. We will never know what numbers might have been scrambled. 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.
“sometimes replaced e.g. 6 with 8, and similar things.”
Xerox scanner compression replaced digits like 6 with 8.
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: this video (german, but there should be news articles from back then in english as well, somewhere)
