A Discussion of Redaction

Interesting.

Posted on April 22, 2013 at 6:36 AM • 7 Comments

Comments

Clive RobinsonApril 22, 2013 9:43 AM

Ahh the joys of "side channels" formed by meta and meta meta data in information. Just deleting the base data is realy not sufficient.

One fun thing that happens is when reports get published in parts. That is names redacted from some parts can be found from circulation lists on other parts or even other documents.

Paul SuhlerApril 22, 2013 12:19 PM

I had a discussion with a Skunk Works senior manager who said that "these old guys" often don't know what's currently sensitive. He was referring to the people I'd been interviewing for my book on the design history of the Blackbird, but the same can be said of the CIA retirees who work as contractors reviewing documents for release.

My favorite declassified document was a report on the deployment of three OXCART (A-12) aircraft to Kadena in 1967. There was a paragraph for each one describing the flight. The first two had the origin ("Area 51") redacted, but it was there for the third.

mooApril 22, 2013 6:28 PM

@Clive Robinson:
The linked discussion has some examples where the exact same document was FOIA-requested from multiple agencies, or from the same agency over a long period of time (years). Different censors made different subjective decisions about what needed to be censored to comply with the classification, especially when it was a borderline case. In some cases, the entire document could be reconstructed because out of 3+ responses, each thing censored in most of the responses would be uncensored in one of them.

The author even acknowledges that its hard to do better than this.. he doesn't seem to be asking for a "more accurate" system, only for the censors to be allocated more resources so they can process his requests in weeks/months instead of years. It struck me that gov't has very little incentive to release the requested information any faster than absolutely necessary. If the office has a 5-year backlog for servicing FOIA requests, most requesters won't have the endurance to stick with it. Whether that serves the interests of transparency and democracy well or not is a different question--it obviously isn't a bad thing for the classifying agency though, as their dirty laundry is less likely to be uncovered in a timely fashion.

paulApril 23, 2013 9:34 AM

For any fact, you can probably find a context in which it should be redacted.

(I think I've already told the one about the security officer telling me with a straight face that the location of Moscow, in combination with some other information, was classified.)

RandomDudeApril 24, 2013 2:00 PM

I actually remember a few years ago starting some talk on some forensic/crypto forums about being able to do text length pattern analysis to figure out what redacted portions of documents said. Not long after that, a new directive came out in which explicitly addressed that issue in future redactions by requiring offcenter "white-boxes" instead of the tranditional "black-marker" approach. Seemed so simple but I failed to find anyone else talking about it. The thing is that it could still be used on old documents.

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