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Be careful what you copy: Invisibly inserting usernames into text
31–40 of 200 posts
Re: Be careful what you copy: Invisibly inserting usernames into text
#32I did this (non-publicly) many years ago for my eve online alliance. A substantial problem exists in that forging the identity of _someone else_ is fairly easy in a naive scheme if someone detects these characters. That means you can sow chaos by blaming innocent folks. In practice you'll want to "sign" the inserted data as well. Also because of the overhead here and the fact that you will want the signature to occur…
I saw the topic and the first thing my mind went to was eve online :) People could still just make a screenshot and the special character would not be visible, so they implemented hidden watermarks: [0] Then the same alliance would also generate slightly different text for each person. [1] I think things might have changed now days, as everyone is recruiting new players and make it easy for other alliances to put spi…
Pandemic Legion? I haven't looked at the articles yet but I swear I remember them doing that in their forums.
Edit: Good old PL.
Re: Be careful what you copy: Invisibly inserting usernames into text
#33 Zero-width characters are invisible, `non-printing' characters that are
not displayed by the majority of applications. F*or exam*ple, I've
ins*erted 10 ze*ro-width spa*ces in*to thi*s sentence, c*an you tel**l?
(Hint: paste the sentence into Diff Checker to see the locations of the
characters!). These characters can be used to `fingerprint' text for
certain users.
Re: Be careful what you copy: Invisibly inserting usernames into text
#34Earlier quoted context omitted.
The 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-th... Another is to alter the _frequency_ of c…
How do you synthetically alter the frequencies of letters?
I'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!
Re: Be careful what you copy: Invisibly inserting usernames into text
#35Earlier quoted context omitted.
The 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-th... Another is to alter the _frequency_ of c…
How do you synthetically alter the frequencies of letters?
It does seem tough to vary word usage to produce the right frequency of letters while keeping the meaning and not having it read awkwardly.
Re: Be careful what you copy: Invisibly inserting usernames into text
#36Earlier quoted context omitted.
The 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-th... Another is to alter the _frequency_ of c…
How do you synthetically alter the frequencies of letters?
The 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.
Re: Be careful what you copy: Invisibly inserting usernames into text
#37This would be an interesting approach to plagiarism detection; I could see how it would be used for a couple of online courses that I use with my students. Of course its just part of the arms race, though.
Re: Be careful what you copy: Invisibly inserting usernames into text
#38How difficult would it be to write a browser extension to either remove all zero-width characters or somehow make it super obvious that they are being used on the page? I just searched for "zero-width" and "zero width" in Chrome and Firefox's extensions stores, but didn't come up with anything.
I don't think that it's too difficult. Just check every tag's text for forbidden characters and replace them with something. I'm not sure about performance.
Re: Be careful what you copy: Invisibly inserting usernames into text
#39Unicode should not have invisible characters.
Then how would you indicate that a space or newline is intended? Or how would I indicate that a length of text is to be displayed from right to left when I post Hebrew text to an English-expecting text field?
Re: Be careful what you copy: Invisibly inserting usernames into text
#40What was the original purpose for these characters' design?
Most certainly HTML layout hacks, like 'I want to create a table with line height but zero width' ;-)
(just kidding)