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Comment by chii | Hacker News Reader

What if you also did a random synonym replacement throughout the piece to destroy the watermarking? If the source is anonymous and hidden, then authenticity cannot be checked by the reader anyway, and so replacement without changing meaning is an acceptable change to protect sources.

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Welcome to the new age of computer-powered math where anonymity is not a guarantee.

Plenty of discussions in this thread show why. Anonymous screenshot or picture? Image watermarks -> anything from subtle color changes, to sans/serif font changes, to word replacement. Anonymous text or summary? Word replacement, letter biasing encoding, etc. Anonymous audio? Inaudible frequencies, audible waveform deformation encoding, etc.

Nothing's out of the realm of possibility for the paranoid.

You would have to change every word, since any could be a waterprinted synonym. A better way would be to read it, make a summary, then rewrite it from memory and only use the source data to correct factual differences.

You wouldn't necessarily have to change every word; just enough to break the decoding scheme. But even then it's totally random, so the longer the document, the more opportunities to be fingerprinted. It's like the old saying goes, "the police only need to be lucky once, but the criminals need to be lucky all the time." [0]

[0] I never bothered looking up where this came from until just now... interestingly it's from the IRA, and used in the total opposite way most people use it now... https://en.wikipedia.org/wiki/Brighton_hotel_bombing

Your saying illustrates what I'm saying perfectly: if you miss even a single fingerprinted word, it might uniquely identify you. So you need to change every single word, and even that isn't enough in case eg. adjectives were added or omitted.

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