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> There are other, far more interesting ways, to watermark text than this that are both harder (to impossible) to detect that produce better results. This soun
by elaus 9y ago
> There are other, far more interesting ways, to watermark text than this that are both harder (to impossible) to detect that produce better results.
This sounds interesting, could you elaborate?
- zbobet2012 9y agoThe post above mentions some. One good way is synonym replacement. In this method the actual _text_ is altered every time to produce a unique arrangement of synonyms used through out the text. For example I can replace "two" with "2" or "fast" with "quick" to obtain a bit to embed things in. See here for examples: http://failheap-challenge.com/showthread.php?16311-Taking-the-meta-seriously-(Part-deux)&p=1047855 http://failheap-challenge.com/showthread.php?16311-Taking-th... Another is to alter the _frequency_ of certain letters occurring in the text to produce a unique watermark. For example the "number of i's" that occur in the text can be used to produce a unique text per user. This is a very hard attack to detect or do anything about because even _summaries_ of the associated text tend to carry letter and word frequencies forward. These methods are also impervious to "screenshot" etc. And because the embedded value can simple be a 64bit key to lookup the users/session info with attacks that attempt to impersonate other are impossible.
- deleted 9y ago[deleted]
- spicyj 9y agoHow do you synthetically alter the frequencies of letters?
- ry_ry 9y agoI'd assume just replace words with synonyms containing the appropriately weighted letter/s? The hard part is going to be keeping the flow of the text, whilst brute forcing a thesaurus into it!
- thinkloop 9y agoIt does seem tough to vary word usage to produce the right frequency of letters while keeping the meaning and not having it read awkwardly.
- zbobet2012 9y agoThe easiest is again to do synonym/word/punctuation replacement but with the intent of altering the letter frequency instead of embedding information directly. It's effectively a compression scheme built on-top of synonym replacement using "extra" available information to pack more bits in less words. This means even sentence long quotes in summary form are enough to compromise someone.
- tjoff 9y agoIt sounds to me that it would be blatantly obvious that a human didn't write whatever result that may produce. And I don't quite get how you can encode that much information in a sentence without it being completely garbled.
- athenot 9y agoIt seems to me that it'd be very obvious that a human did not write whatever result that could produce. Here's 5 bits in that simple sentence. I'm sure others can do better.
- specialist 9y agoIt now occurs to me: inject common proofreading mistakes that often go unnoticed.
- chatmasta 9y agoI can see a lot of problems with showing different texts to different users in the same place. For example: - on a forum, if the post reads slightly different to each user, and one user “quotes” it, the quote will be of what that user saw, and other users will be able to identify the fingerprint from the quote. - if the fingerprinting script modifies all posts on the forum, then a poster will be alarmed to see his words change. There are clever ways around both of these issues (rewriting the quotes on render, and hiding the fingerprinting from the OP). But eventually the system gets pretty complicated, and ultimately you’re visibly presenting different text to different users, so it’s no longer an invisible fingerprint.
- amelius 9y ago> on a forum, if the post reads slightly different to each user, and one user “quotes” it, the quote will be of what that user saw, and other users will be able to identify the fingerprint from the quote. Not if the forum intelligently changes the quoted text :)
- gruez 9y agohow do you handle partial quotes? what about broken quotes?
- itronitron 9y agointeresting, I wonder if that is why there are so many typos and grammatical errors in news articles these days