Comment by gorgoiler | Hacker News Reader

Comment by gorgoiler | Hacker News Reader

This is fascinating and really made me think. The article is pitched at leakers but it could just as likely be pitched at journalists. If you consume news from an outlet that doesn’t follow The Intercept’s advice then complain immediately to the editor.

When you leak something it needs to be credible. Removing watermarks also reduces the fidelity and therefore the credibility. If 99% of the screen is blurred and the audio has been transcribed then how does the receiver know this is a real leak at all?

The answer lies in reputation. Leak high fidelity material to a trusted third party, usually a journalist. This can include just showing them the material though that involves meeting in person. They will verify the source material, summarise and down sample it to conceal the source actor, and maybe even destroy the source material itself.

The economics are simple: if you get a reputation for revealing sources then people will stop leaking secrets to you. Newsrooms that rebroadcast Zoom caps verbatim are revealing sources and need to clean up their act if we are to continue to rely on what’s left of The Fourth Estate.

There are flaws with this model, here is an example (which would never have been revealed if the documents had not been released): https://en.wikipedia.org/wiki/Killian_documents_controversy

I can think of others ways this sort of thing could occur, with the document being ‘real’. Some photocopiers use text recognition and so presumably just attempt a font match when printing. This has caused issues in the past and could cause this sort of confusion too (although this seems a smear attempt).

https://news.ycombinator.com/item?id=9584172

The article says CBS received downsampled copies. They failed to do due diligence, but they would have outed the hoax had they seen the “original” documents?

Well, CBS wanted a story to be true. But I assume it would have been much easier for experts to determine if something was typed a number of decades ago vs. laser printed recently. (As opposed to finding typographic discrepancies in a relatively low fidelity copy.)

It's worth remembering that the Intercept hardly has a stellar reputation for protecting sources: they completely bungled the Reality Winner leak.

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

Yes, and while they never properly owned up to this, it seems (from this article and others) that they learned from it and are trying to avoid a repeat.

Though I haven't seen them post an article describing in detail how watermarks on color laser printers work, that would be a bit too on-the-nose.

The damage has already been done. Glenn Greenwald and Laura Poitras were pushed out. The Intercept has shown their true colors at this point.

> If 99% of the screen is blurred and the audio has been transcribed then how does the receiver know this is a real leak at all?

There is probably a way to eliminate the possibility of revealing the source without compromising any significant amount of fidelity.

Not really. Imagine you want to leak a one page printed document.

If the covert signal (the employee ID of the leaker) is encoded with tiny dots then it could be filtered in or out with a band pass filter. Filtering out the data can be done with a fax machine if you can find one.

But if the covert data is embedded in the original signal at frequencies close to the signal “frequency” then you don’t stand a chance. The information band of written English provides a huge number of options for hiding other signals: spelling, choice of words, spacing, key phrases, capitalisation, the ordering of items in a list.

The government agency from where you are leaking — your adversary — has the original signal from which they adapted your slightly different copy that you leaked. All they have to do is hide 6 to 16 bits of data in 2kb of English language. This is trivial because they have the original plaintext with which to encode and later extract the signal.

How do you effectively tackle this, as a leaker? A journalist is the one type of filter capable of obscuring covert traffic at these frequencies. They read the document, summarise the implications, and then write that up. I probably wouldn’t let them keep the original text though.

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