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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

#71

Post by layer8 »

cubefox wrote: post #65
layer8 wrote: post #61

Earlier quoted context omitted.

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…

I'm pretty sure you can change various file formats without rewriting the entire file and without using "incremental updates".

You can’t insert data into the middle of a file (or remove portions from the middle of a file) without either rewriting it completely, or at least rewriting everything after the insertion point; the latter requires holding everything after the insertion point in memory (or writing it out to another file first, then reading it in and writing it out again).

PDF is designed to not require holding the complete file in memory. (PDF viewers can display PDFs larger than available memory, as long as the currently displayed page and associated metadata fits in memory. Similar for editing.)

Re: New information extracted from Snowden PDFs through metadata version analysis

#72

Post by cubefox »

mattzito wrote: post #70
cubefox wrote: post #65

Earlier quoted context omitted.

I'm pretty sure you can change various file formats without rewriting the entire file and without using "incremental updates".

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?

Re: New information extracted from Snowden PDFs through metadata version analysis

#74

Post by anticodon »

jfengel wrote: post #43
anticodon wrote: post #34

Earlier quoted context omitted.

What Russia and China has in common? Why would somebody work for both countries? Do you know, for example, that China willingly sells huge amounts of drones to Ukraine?

Here in 2026 China is supplying Russia with weapons in exchange for oil under global sanctions. Russia is in no position to reject China for selling to both sides. They may not be allies but each is the enemy of their enemies.

Which exactly weapons are supplied by China? Even ever lying news sources like Bloomberg and CNN never made such unfounded accusations.

Also, how and why some "spy" would work both for China and Russia? Two very different countries from every point of view: culturally, economically, and in every other way also.

The only thing in common is that USA wants to destroy both Russia and China and that because of that reason US controlled media (like 90% of media in the world) publish scary fakes about both countries.

Re: New information extracted from Snowden PDFs through metadata version analysis

#76

Post by layer8 »

cubefox wrote: post #72
mattzito wrote: post #70

Earlier 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?

Look at the C file API which most software is based on, it simply doesn’t allow it. Writing at a given file position just overwrites existing content. There is no way to insert or remove bytes in the middle.

Apart from that, file systems manage storage in larger fixed-size blocks (commonly 4 KB). One block typically links to the next block (if any) of the same file, but that’s about the extent of it.

Re: New information extracted from Snowden PDFs through metadata version analysis

#77

Post by nwallin »

everdrive wrote: post #41
cookiengineer wrote: post #37

Earlier quoted context omitted.

> 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. Note that all (edit: color-/ink-) printers have "invisible to the human eye" yellow dotcodes, which contain their serial number, and in some cases even the public IP address when they've already connected to the internet (looking at you, HP and Canon). So…

>Note that all printers have "invisible to the human eye" yellow dotcodes, which contain their serial number, and in some cases even the public IP address when they've already connected to the internet (looking at you, HP and Canon). I've got a black and white brother printer which uses toner. Is there something similar for this printer?

It's only there for color printers.

A tiny yellow dot on white paper is basically invisible to the human eye. Yellow ink absorbs blue light and no other light, and human vision is crap at resolving blue details.

A tiny black dot on white paper sticks out like a sore thumb.

Re: New information extracted from Snowden PDFs through metadata version analysis

#78

Post by mmh0000 »

cookiengineer wrote: post #37
password4321 wrote: post #16

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.

> 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. Note that all (edit: color-/ink-) printers have "invisible to the human eye" yellow dotcodes, which contain their serial number, and in some cases even the public IP address when they've already connected to the internet (looking at you, HP and Canon). So…

If you have a UV flashlight, these dots are visible with decent vision.

And of course we have to include the Wikipedia entry:

https://en.wikipedia.org/wiki/Printer_tracking_dots

Re: New information extracted from Snowden PDFs through metadata version analysis

#79

Post by dredmorbius »

JumpinJack_Cash wrote: post #59
password4321 wrote: post #16

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.

Is there a multifunction B&W printer which prints and then automatically positions the paper on the scanner and scans?

Far more straightforward to print a stack, then feed that stack through the copier/scanner.

Re: New information extracted from Snowden PDFs through metadata version analysis

#80

Post by CamperBob2 »

dfreel wrote: post #20
Andrex wrote: post #14

Earlier quoted context omitted.

The best way to fix a problem is to bring it into the light, not pretend it doesn't exist. "Security by obscurity" has been debunked for decades. If our system is so flawed Snowden's leaks would have blown everything up, maybe the system deserves to be blown up. Otherwise we're just papering over flaws which likely will be discovered and exploited eventually.

[flagged]

Given that our incompetent security policies apparently granted full access to people with no conceivable need to know (see also Manning), the bad guys already had all that stuff. If that wasn't the case before, it certainly is now, with Trump in office.

Law-abiding US citizens are pretty much the only ones who didn't know what was being done in their names. That's the only thing the Snowden disclosures changed.

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