The "print and scan physical papers back to a PDF of images" technique for final release is looking better and better from an information protection perspective.
That'd be fun to make Section 508 compliant at mass scale.
New information extracted from Snowden PDFs through metadata version analysis
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Re: New information extracted from Snowden PDFs through metadata version analysis
#92Earlier quoted context omitted.
Far more straightforward to print a stack, then feed that stack through the copier/scanner.
You don't need to actually print and scan. Just convert to a raster format like PNG.
Then use OCR to convert it back from raster for Section 508 compliance. All the existing work to make handwritten pages and visuals compliant would have to be redone after converting to raster.
Re: New information extracted from Snowden PDFs through metadata version analysis
#93Earlier quoted context omitted.
It's hilarious the extent to which Adobe Systems's ridiculously futile attempt to chase MS Word features ended up being the single most productive espionage tool of the last quarter century.
I don’t think this was particularly modeled on MS Word. The incremental update feature was introduced with PDF 1.2 in 1996. It allows to quickly save changes without having to rewrite the whole file, for example when annotating a PDF. Incremental updates are also essential for PDF signatures, since when you add a subsequent signature to a PDF, you couldn’t rewrite the file without breaking previous signatures. Hence…
PDF files are for storing fixed (!!) output of printed/printable material. That's where the format's roots are via Postscript, it's where the format found its main success in document storage, and it's the metaphor everyone has in mind when using the format.
PDFs don't change. PDFs are what they look like.
Except they aren't, because Adobe wanted to be able to (ahem) "annotate" them, or "save changes" to them. And Adobe wanted this because they wanted to sell Acrobat to people who would otherwise be using MS Word for these purposes.
And in so doing, Adobe broke the fundamental design paradigm of the format. And that has had (and continues to have, to hilarious effect) continuing security impact for the data that gets stored in this terrible format.
Re: New information extracted from Snowden PDFs through metadata version analysis
#94The "print and scan physical papers back to a PDF of images" technique for final release is looking better and better from an information protection perspective.
I suppose I'd just save the pdf to tiff/png then remake back into a pdf from there to avoid printing and scanning? if really paranoid, I suppose one could run a filter on the image files to make them a bit fuzzy/noisy
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Re: New information extracted from Snowden PDFs through metadata version analysis
#95Earlier quoted context omitted.
No, if you are going to change the structure of a structured document that has been saved to disk, your options are: 1) Rewrite the file to disk 2) Append the new data/metadata to the end of the existing file I suppose you could pre-pad documents with empty blocks and then go modify those in situ by binary editing the file, but that sounds like a nightmare.
Aren't there file systems that support data structures which allow editing just part of the data, like linked lists?
Yeah there are, Linux supports parameters FALLOC_FL_INSERT_RANGE and FALLOC_FL_COLLAPSE_RANGE for fallocate(2). Like most fancy filesystem features, they are not used by the vast majority of software because it has to run on any filesystem so you'd always need to maintain two implementations (and extensive test cases).
Re: New information extracted from Snowden PDFs through metadata version analysis
#96[flagged]
Are you asking how much was done with pen and paper, and how much of it was done on a computer, i.e. machine assisted? Where do you draw the line? How is "hands-on" in contrast to anything? Is it only "hands-on" when you don't use any tool to assist you?
I suspect you're inquiring about the use of LLMs, and about that I wonder: Why does it matter? Why are you asking?
Re: New information extracted from Snowden PDFs through metadata version analysis
#97In addition to the print paper and scan approach, I do wonder how effective it would be to “Print to XPS” and then “print” that into a PDF.
Re: New information extracted from Snowden PDFs through metadata version analysis
#98The "print and scan physical papers back to a PDF of images" technique for final release is looking better and better from an information protection perspective.
a better approach is to convert them to jpeg/png. Then convert that to raw BMP, and then share or print that.
A more modern approach for text documents would be to have an LLM read and rephrase, and restructure everything without preserving punctuation and spacing, using a simple encoding like utf-8, and then use the technique above or just take analog pictures of the monitor. The analog (film) part protects against deepfakes and serves as proof if you need it (for the source and final product alike).
There various solutions out there after the leaks that keep happening where documents and confidential information is served/staged in a way that will reveal the person with who it is shared. Even if you copy paste the text into notepad and save it in ascii format, it will reveal you. Off-the-shelf printers are of course a big no-no.
If all else fails, that analog picture technique works best for exfil, but the final thing you share will still track back to you. I bet spies are back to using microfilms these days.
I only say all of that purely out of a fascination into the subject and for the sake of discussion (think like a thief if you want to catch one and all). Ultimately, you shouldn't share private information with unauthorized parties, period. Personal or otherwise. If you, like snowden, feel that all lawful means are exhausted and that is your only option to address some grievance, then don't assume any technique or planning will protect you, if it isn't worth the risk of imprisonment, then you shouldn't be doing it anyways. Assume you will be imprisoned or worse.
Re: New information extracted from Snowden PDFs through metadata version analysis
#99Can someone spell out how this is possible? Do pdfs store a complete document version history? Do they store diffs in the metadata? Does this happen each time the document is edited?
At the bottom of the page there's a link to the pdfresurrect package, whose description says "The PDF format allows for previous changes to be retained in a revised version of the document, thereby keeping a running history of revisions to the document. This tool extracts all previous revisions while also producing a summary of changes between revisions."
Re: New information extracted from Snowden PDFs through metadata version analysis
#100There needs to be better tooling for inspecting PDF documents. Right now, my needs are met by using `qpdf` to export QDF [1], but it is just begging for a GUI to wrap around it... [1] https://qpdf.readthedocs.io/en/stable/qdf.html
Take a look at the REMNux reverse engineering page for PDF documents (https://docs.remnux.org/discover-the-tools/analyze+documents...). Lots of tools here for looking at malicious PDFs that can be used to inspect/understand even non-malicious documents.