5 ms·

No, we worked with researchers that developed that kind of system, but didn't broadcast our work b/c the research was too sensitive. Seems the cat is out the ba

No, we worked with researchers that developed that kind of system, but didn't broadcast our work b/c the research was too sensitive. Seems the cat is out the bag now though. I think the combination of AI and font-metrics is going to be wild though. You ought to be able to make a system that can figure out likely words based on the unredacted ones and the redaction's size. I haven't seen any redaction system yet that protects against this.

thangalin 9mo ago
> I haven't seen any redaction system yet that protects against this. The linked article suggests widening redacted areas more than needed with some randomization applied to the width. Strikes me that that wouldn't do much except add a few more possible solutions.
- vlovich123 9mo ago
  Yeah, the more robust protection is to widen to a constant. But in the general case that could require reflowing the pdf. But honestly single word redactions are really probably useless with cheap AI that can highly accurately fill in the gaps
  - rgmerk 9mo ago
    Depends what you're trying to hide. If the redaction is a person's name, and there's nothing else to give the person's identity away, single word redaction probably works reasonably well, AI or no AI.
    - godelski 9mo ago
      > If the redaction is a person's name I'm not sure if you're aware, but peoples names are variable in length. We are talking about a system that can identify single character differences. So that does reduce the search space, especially since names are not all possible letter permutations. Combine that with the fact that it isn't uncommon to see partial first letters show up. You can even see some instances in the Epstein files. Of course, you can also take this further. Even if you can't recover names you can get meta information about how many parties are involved by recognizing different length redactions correspond to different entities. While same length redaction doesn't guarantee same entity it is a hint.
      - mycall 9mo ago
        It is also common for authors to misspell names (proper nouns) in an attempt to determine who leaks docs (and to force non-matches for FOIA requests).
        mhast 9mo ago
        If you want to fingerprint text you can also do it by small insignificant changes to text which doesn't change the meaning. If you have a number such locations with alternatives then you can make a number of identifiable versions by combining alternates.
        godelski 9mo ago
        Random side fact but this was also a thing map makers did back in the day. Including fake towns. In that way they could identify who was stealing their work.
vlovich123 9mo ago
I thought glyph spacing attacks are an old idea; like I recall reading about such ideas 10-20 years ago unless I’m misremembering. Can you clarify why it was considered “too sensitive” if the whole point of this effort is to showcase these attacks?
- mlissner 9mo ago
  It’s a fine line. Most redactions are for the good, to protect someone or something. For example even in the Epstein files, where some redactions are being abused, most redactions are protecting victims. If there’s a way to undo huge amounts of redactions, that’d certainly be a net negative. Sort of like if encryption were suddenly broken, you wouldn’t publish a paper saying so. Our goal has always been to educate about the problem so that it can be addressed. We didn’t have resources to push on the font metrics approach, so we stayed mostly quiet about it.
  - btreecat 9mo ago
    > If there’s a way to undo huge amounts of redactions, that’d certainly be a net negative. Sort of like if encryption were suddenly broken, you wouldn’t publish a paper saying so. I can't state emphatically enough how this is not the right mental playbook. If you have found a vulnerability, it's likely someone else has too. By sitting on it, you only create more future victims. Disclosure will lead to fixing this issue, mitigating it's precense, or switching tools/workflows, possibly a combination of. Sitting on it only ensures that folks who think they are protected, actually aren't.
    - mlissner 9mo ago
      We’re familiar with vulnerability disclosure philosophies, but what if the problem can’t be fixed because there’s no forward secrecy for the hundreds of millions of documents that are already out there? It’s tricky stuff and we have limited resources, unfortunately.
      - opello 9mo ago
NoboruWataya 9mo ago
This is going to be a disaster IMO because AI will just hallucinate what it thinks is the most probable redacted word and people will take that as gospel.
- PunchyHamster 9mo ago
  "don't redact or we will hallucinate something worse and make people believe it as gospel" is nice deterrent
  - rafram 9mo ago
    We don’t need a “deterrent” against things being redacted in publicly released documents. We can have transparency without the whole world finding out the names of victims and witnesses, people’s phone numbers and SSNs, etc., every time a document is released.
hahn-kev 9mo ago
Maybe we should all just use mono-space fonts for everything

thangalin 9mo ago

> I haven't seen any redaction system yet that protects against this. The linked article suggests widening redacted areas more than needed with some randomization applied to the width. Strikes me that that wouldn't do much except add a few more possible solutions.

vlovich123 9mo ago
Yeah, the more robust protection is to widen to a constant. But in the general case that could require reflowing the pdf. But honestly single word redactions are really probably useless with cheap AI that can highly accurately fill in the gaps
- rgmerk 9mo ago
  Depends what you're trying to hide. If the redaction is a person's name, and there's nothing else to give the person's identity away, single word redaction probably works reasonably well, AI or no AI.
  - godelski 9mo ago
    > If the redaction is a person's name I'm not sure if you're aware, but peoples names are variable in length. We are talking about a system that can identify single character differences. So that does reduce the search space, especially since names are not all possible letter permutations. Combine that with the fact that it isn't uncommon to see partial first letters show up. You can even see some instances in the Epstein files. Of course, you can also take this further. Even if you can't recover names you can get meta information about how many parties are involved by recognizing different length redactions correspond to different entities. While same length redaction doesn't guarantee same entity it is a hint.
    - mycall 9mo ago
      It is also common for authors to misspell names (proper nouns) in an attempt to determine who leaks docs (and to force non-matches for FOIA requests).
      - mhast 9mo ago
        If you want to fingerprint text you can also do it by small insignificant changes to text which doesn't change the meaning. If you have a number such locations with alternatives then you can make a number of identifiable versions by combining alternates.
      - godelski 9mo ago
        Random side fact but this was also a thing map makers did back in the day. Including fake towns. In that way they could identify who was stealing their work.

vlovich123 9mo ago

I thought glyph spacing attacks are an old idea; like I recall reading about such ideas 10-20 years ago unless I’m misremembering. Can you clarify why it was considered “too sensitive” if the whole point of this effort is to showcase these attacks?

mlissner 9mo ago
It’s a fine line. Most redactions are for the good, to protect someone or something. For example even in the Epstein files, where some redactions are being abused, most redactions are protecting victims. If there’s a way to undo huge amounts of redactions, that’d certainly be a net negative. Sort of like if encryption were suddenly broken, you wouldn’t publish a paper saying so. Our goal has always been to educate about the problem so that it can be addressed. We didn’t have resources to push on the font metrics approach, so we stayed mostly quiet about it.
- btreecat 9mo ago
  > If there’s a way to undo huge amounts of redactions, that’d certainly be a net negative. Sort of like if encryption were suddenly broken, you wouldn’t publish a paper saying so. I can't state emphatically enough how this is not the right mental playbook. If you have found a vulnerability, it's likely someone else has too. By sitting on it, you only create more future victims. Disclosure will lead to fixing this issue, mitigating it's precense, or switching tools/workflows, possibly a combination of. Sitting on it only ensures that folks who think they are protected, actually aren't.
  - mlissner 9mo ago
    We’re familiar with vulnerability disclosure philosophies, but what if the problem can’t be fixed because there’s no forward secrecy for the hundreds of millions of documents that are already out there? It’s tricky stuff and we have limited resources, unfortunately.
    - opello 9mo ago

NoboruWataya 9mo ago

This is going to be a disaster IMO because AI will just hallucinate what it thinks is the most probable redacted word and people will take that as gospel.

PunchyHamster 9mo ago
"don't redact or we will hallucinate something worse and make people believe it as gospel" is nice deterrent
- rafram 9mo ago
  We don’t need a “deterrent” against things being redacted in publicly released documents. We can have transparency without the whole world finding out the names of victims and witnesses, people’s phone numbers and SSNs, etc., every time a document is released.

hahn-kev 9mo ago

Maybe we should all just use mono-space fonts for everything