Somebody ought to train an LLM exclusively on this text, just for funsies.
A case study in PDF forensics: The Epstein PDFs
21–30 of 254 posts
Re: A case study in PDF forensics: The Epstein PDFs
#22> DoJ explicitly avoids JPEG images in the PDFs probably because they appreciate that JPEGs often contain identifiable information, such as EXIF, IPTC, or XMP metadata Maybe I'm underestimating the issue at full, but isn't this a very lightweight problem to solve? Is converting the images to lower DPI formats/versions really any easier than just stripping the metadata? Surely the DOJ and similar justice agencies have…
Maybe they know more than we do. It may be possible to tamper with files at a deeper level. I wonder if it is also possible to use some sort of tampered compression algorithm that could mark images much like printers do with paper.
Another guess is that perhaps the step is a part of a multi-step sanitation process, and the last step(s) perform the bitmap operation.
Re: A case study in PDF forensics: The Epstein PDFs
#23Any guesses why some of the newest files seem to have random ”=” characters in the text? My first thought was OCR, but it seemed to not be linked to characters like ”E” that could be mistakenly interpreted by an OCR tool. My second guess is just making it more difficult to produce reliable text searches, but probably 90% of HN readers could find a way to make a search tool that does not fall apart in case a ”=” chara…
Was on the frontpage yesterday: https://news.ycombinator.com/item?id=46868759
Thanks a lot!
Re: A case study in PDF forensics: The Epstein PDFs
#24Earlier quoted context omitted.
[flagged]
Haven't seen anything particular about that, but lots of the documents with names that were half-redacted contain OCRd text that is completely garbled, but olmocr-2-7b seems to handle it just fine. Unsure if they just had sucky processes or if there is something else going on.
Might be a good fit for uploading a git repo and crowdsourcing
Re: A case study in PDF forensics: The Epstein PDFs
#25Any guesses why some of the newest files seem to have random ”=” characters in the text? My first thought was OCR, but it seemed to not be linked to characters like ”E” that could be mistakenly interpreted by an OCR tool. My second guess is just making it more difficult to produce reliable text searches, but probably 90% of HN readers could find a way to make a search tool that does not fall apart in case a ”=” chara…
The equal characters are due to poor handling of quoted-printable in email.
The author of gnus, Lars Ingebrigtsen, wrote a blog post explaining this. His post was on the HN front page today.
Re: A case study in PDF forensics: The Epstein PDFs
#26> Information leakage may also be occurring via PDF comments or orphaned objects inside compressed object streams, as I discovered above. hopefully someone is independently archiving all documents my understanding is that some are being removed
Are they being removed or replaced with more heavily redacted documents? There were definitely some victim names that slipped through the cracks that have since been redacted.
Re: A case study in PDF forensics: The Epstein PDFs
#27Somebody ought to train an LLM exclusively on this text, just for funsies.
DeepSeek-V4-JEE
Re: A case study in PDF forensics: The Epstein PDFs
#28Any guesses why some of the newest files seem to have random ”=” characters in the text? My first thought was OCR, but it seemed to not be linked to characters like ”E” that could be mistakenly interpreted by an OCR tool. My second guess is just making it more difficult to produce reliable text searches, but probably 90% of HN readers could find a way to make a search tool that does not fall apart in case a ”=” chara…
The equal characters are due to poor handling of quoted-printable in email. The author of gnus, Lars Ingebrigtsen, wrote a blog post explaining this. His post was on the HN front page today.
He explained the newline thing that confused me. Good read!
Re: A case study in PDF forensics: The Epstein PDFs
#29> Information leakage may also be occurring via PDF comments or orphaned objects inside compressed object streams, as I discovered above. hopefully someone is independently archiving all documents my understanding is that some are being removed
I think some of the released documents included images of victims, which where redacted. So it's not necessarily malicious removals
Re: A case study in PDF forensics: The Epstein PDFs
#30> DoJ explicitly avoids JPEG images in the PDFs probably because they appreciate that JPEGs often contain identifiable information, such as EXIF, IPTC, or XMP metadata Maybe I'm underestimating the issue at full, but isn't this a very lightweight problem to solve? Is converting the images to lower DPI formats/versions really any easier than just stripping the metadata? Surely the DOJ and similar justice agencies have…
Maybe they know more than we do. It may be possible to tamper with files at a deeper level. I wonder if it is also possible to use some sort of tampered compression algorithm that could mark images much like printers do with paper. Another guess is that perhaps the step is a part of a multi-step sanitation process, and the last step(s) perform the bitmap operation.
I'm not sure about computer image generation but you can (relatively) easily fingerprint images generated by digital cameras due to sensor defects. I'll bet there is a similar problem with PC image generation where even without the EXIF data there is probably still too much side channel data leakage.