Stories
Slash Boxes
Comments

SoylentNews is people

posted by Fnord666 on Thursday April 05 2018, @08:27PM   Printer-friendly
from the digital-fingerprints dept.

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.

Well, the original reason isn’t too exciting. A few years ago I was a member of a team that participated in competitive tournaments across a variety of video games. This team had a private message board, used to post important announcements amongst other things. Eventually these announcements would appear elsewhere on the web, posted to mock the team and more significantly; ensuring the message board was redundant for sharing confidential information and tactics.

The security of the site seemed pretty tight so the theory was that a logged-in user was simply copying the announcement and posting it elsewhere. I created a script that allowed the team to invisibly fingerprint each announcement with the username of the user it is being displayed to.

I saw a lot of interest in zero-width characters from a recent post by Zach Aysan so I thought I’d publish this method here along with an interactive demo to share with everyone. The code examples have been updated to use modern JavaScript but the overall logic is the same.


Original Submission

 
This discussion has been archived. No new comments can be posted.
Display Options Threshold/Breakthrough Mark All as Read Mark All as Unread
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
  • (Score: 2) by tangomargarine on Friday April 06 2018, @04:23PM (3 children)

    by tangomargarine (667) on Friday April 06 2018, @04:23PM (#663473)

    Monospace + zero-width = Monospace. Every character in your monospaced text can have 0 or 1 units of width.

    So what you're saying is that mono-spaced fonts can have 2 spacings. Marvelous.

    --
    "Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
    Starting Score:    1  point
    Karma-Bonus Modifier   +1  

    Total Score:   2  
  • (Score: 2) by takyon on Friday April 06 2018, @04:31PM (2 children)

    by takyon (881) <reversethis-{gro ... s} {ta} {noykat}> on Friday April 06 2018, @04:31PM (#663477) Journal

    Every character you don't type takes up "space". "Zero space".

    --
    [SIG] 10/28/2017: Soylent Upgrade v14 [soylentnews.org]
    • (Score: 2) by tangomargarine on Friday April 06 2018, @06:22PM (1 child)

      by tangomargarine (667) on Friday April 06 2018, @06:22PM (#663502)

      Not the same thing at all.

      --
      "Is that really true?" "I just spent the last hour telling you to think for yourself! Didn't you hear anything I said?"
      • (Score: 2) by Osamabobama on Friday April 06 2018, @10:16PM

        by Osamabobama (5842) on Friday April 06 2018, @10:16PM (#663560)

        It's the difference between looking at the front face of a character, or the side edge. Edge-on, the characters are impossible to see, but they are still there. Unless they aren't there, as suggested above.

        Do modern typesetters get paid by the letter? I smell a scam...

        --
        Appended to the end of comments you post. Max: 120 chars.