Lets say you are an Cuban spy inside the NSA. While you copy memos you notice a watermark with your personal NSA employee ID embedded in the paper.

The NSA might have spies inside the Cuban intelligence services. If you remove the water mark, the NSA will you that you know about their counter intelligence.

If you leave the watermark in they know you are the spy. But, if you change the watermark to some ID from another employee there will be no downside for you. And you start tension within the NSA.

Maybe you can even turn the burned innocent employee, because he will be pissed at the NSA.

Eve is like that.

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Reminds me of a story. That one time there was a large battle in eve. If you want to repair / heal a friendly ship in eve you have to target it, and press F1 to start your remote rapair module (healing spell).

In the heat of the battle the pilot Ivory, a healer from Team A, messed up and accidentally targeted the enemy ship his fleet what shooting at the time. He did not notice his mistake and shouted "All reps on Cain!" (Use healing spells on the pilot Cain) Cain was from Team B.

Counter intelligence officers from Team A thought that our healer Ivory was a spy and just pressed the wrong push-to-talk button in TeamSpeak. They sifted through logs and found out his IP, he was from Alberta, CA. Just like the leader from TeamB.

Team A set a trap and killed a expensive ship from Ivory .. and kicked from the Alliance (Guild)

Ivory was not a spy :) Internet spaceships are serious business.

How did you find out he wasn't a spy?

I think a week later Team A apologized, replaced his ship and took him back.

But the accusation was stupid to begin with. He was a loyal member for years, living in the same Canadian state as another eve player is not really uncommon any shouting on TeamSpeak who is currently getting shot would not have been helpful.

Diplomats from Team B said he was not a spy.

Spying is a big problem in Eve. At the most basic level a spy is able to take screenshots and copy/paste text to send back to the entity they're spying for. By watermarking both text and forum backgrounds the data effectively becomes tainted in the sense that the screenshot/text will have unique characteristics that allow the original poster to identify who copied the data in the first place.

The whole flow would be:

- X is a player in alliance FOO but is actually an agent planted there by alliance BAR.

- Y is a player in alliance BAR but is actually an agent planted there by alliance FOO (or any other).

- X copies intel from FOO's forums and sends it back to the people in charge of the spy program in BAR.

- That intel gets shared with key personnel in alliance BAR, so they can take action based on the gathered intelligence; unknown to BAR, among that personnel is Y

- Y sees that intel and sends it back to their leadership in alliance FOO

- The people at alliance FOO identify the unique data on that intel and track it down to X and proceed to kick him for being a spy.

As someone who is involved with alliance leadership stuffs: This may sound convoluted but it's really bread-and-butter level stuff in Eve, it can get significantly weirder. For example this article discusses whitespace character-based fingerprinting: that's amateur level, like described elsewhere in this thread.

To answer your question: counter-intelligence. If your method for tagging data is known and easy to replicate, such as watermarking your forum userID in screenshots, the people at alliance BAR can edit the screenshot (or forge a new one) where they insert the userID of an innocent person in alliance FOO in the gathered intel, this way when Y grabs the data for sending back to FOO, they'll be unknowingly sending evidence that incriminates a loyal member.

edit: I noticed I didn't address your last question. Signing data is just regular cryptographic signing yeah, in the above example to prevent tampering you'd insert the hash from the userID plus a secret salt for example. You just need some way to prevent the hostiles from incriminating someone else.

> The people at alliance FOO identity the unique data on that intel and track it down to X and proceed to kick him for being a spy.

That, or deliberately feed misinformation to the spy.

Screenshots made in World of Warcraft contain a watermark which contains the account number of the player, as well as other info [1] [2]. This is used to find/combat cheaters (e.g. botters).

As for spying, I'm pretty sure this is a problem in high end raiding in WoW. But due to the nature of WoW (not being a king of the hill MMO to rule land) not nearly as much as EVE. Blizzard uses it to combat cheating.

[1] http://www.tomshardware.com/news/watermark-screenshots-World...

[2] https://eric-diehl.com/world-of-warcraft-and-watermarking/

Couldn't someone just black out the watermark?

In this case not. The watermark is all over the place, viewable when you zoom in. The alternative is to use a 3rd party tool to make screenshots such as Greenshot, ShareX, or Gyazo.

Could "fingerprinting" a screenshot be foiled by running the screenshot through a lossy algorithm? Or doing something like converting to jpg->gif->jpg->gif->png->jpg... a few rounds? Enough to keep the picture viewable, but just barely?

Or hell, even simpler; taking a cameraphone picture of the screenshot?

Depends on the type of fingerprinting used. The example I mentioned with the invisible pattern yes but if the fingerprinting is done via other means such as replacing some words on a post with synonyms for each user in such a way that each has a unique combination of words it wouldn't work.

Generally speaking in these scenarios you don't want to grab anything directly from the source, just relay what you saw and write it down in your own words. Even then it has to be handled carefully (how many other people got this information? Are the details I'm seeing slightly incorrect in order to filter out who leaked this?)

Also take into account that you can be caught just by repeated "A/B testing" of sorts: half the population gets informed that at 19:05 some operation is taking place, the other half that the op is taking place at 19:10. The next day they do the same but using different groups, if you have access to the data that is being leaked you can track down who is leaking it like that after a few iterations.

The in-game stuff is the tip of the PVP iceberg as far as Eve goes. Whole alliances have been killed off using a handful of reddit sockpuppets impersonating their members, brought down by a player flipped at a social event, or simply imploded under the weight of internal drama stoked by rivals. Often all 3 at the same time.

It's a very interesting game, built on a really crappy space themed spreadsheet.