Game of Thrones leak and watermark: a stupid tracking system • Hacker News Board

Re: Game of Thrones leak and watermark: a stupid tracking system

#31

Post by TheLoneWolfling » Mon, Apr 13, 2015, 2:09 PM UTC

zapu wrote: post #20

NoMoreNicksLeft wrote: post #5

Not very clever. Get two leaked copies, and mix them up. Use the credits from copy A, or hell, even chop off 11 milliseconds from them. Then mix and match scenes... even chop off a few ms from some randomly selected scenes. I bet you wouldn't even need the two copies.

Only if you knew that was already going on. Security by obscurity, but still, I don't believe this kind of watermarking was ever used. Maybe something like Cinavia[1] could be used instead? It's an analog watermarking system for detecting pirated copies and refusing to play them if player detects such copy is played on something else than bluray disc. Apparently this survives transcoding, and was/is major pain for pe…

Step 1: setup an automated setup for playing video and detecting if the output was detected via the watermarking system.

Step 2: Run the whole thing through an optimizer seeking to minimize error while not being detected.

Step 3: Wait a few hours.

Re: Game of Thrones leak and watermark: a stupid tracking system

#32

Post by markbnj » Mon, Apr 13, 2015, 2:09 PM UTC

fredley wrote: post #2

...or just use steganography. Steganography in videos can be made to be invisible to the naked eye, and extremely robust - even to video compression. It's also difficult to detect, and even more difficult to remove/tamper with. What the author of the article is proposing is actually a kind of steganography, albeit a rather crude one, and probably rather difficult to implement (since scene timings will be different fo…

Came in to say this. It's the obvious answer, and presumably the IP owners know about it even if the author of the article does not. It's also obvious that the author doesn't understand video encoding if he is proposing measuring millisecond differences in the length of specific scenes.

Re: Game of Thrones leak and watermark: a stupid tracking system

#33

Post by shawabawa3 » Mon, Apr 13, 2015, 2:09 PM UTC

erikb wrote: post #3

I guess we all agree that watermarking the viewable content instead of thinking about securing/signing the whole data file was not so smart in the first place. When I download a video from the Google Play Store I can only watch it for 24 hours or so. I thought there was already a highly protected digital signature/encryption system involved. Why is that not used for reporter previews?

Anything that is viewable cannot be secured.

The play store can stop you watching the content after 24 hours on the play store. It cannot possibly stop you recording your screen while it's playing and saving it forever

Preventing leaks is basically impossible, but making them traceable is possible using watermarks

Re: Game of Thrones leak and watermark: a stupid tracking system

#34

Post by fredley » Mon, Apr 13, 2015, 2:09 PM UTC

NoMoreNicksLeft wrote: post #7

fredley wrote: post #2

...or just use steganography. Steganography in videos can be made to be invisible to the naked eye, and extremely robust - even to video compression. It's also difficult to detect, and even more difficult to remove/tamper with. What the author of the article is proposing is actually a kind of steganography, albeit a rather crude one, and probably rather difficult to implement (since scene timings will be different fo…

How will that survive transcoding? What if you bump it down to 477p resolution?

There will be a limit to how much compression it can take, but some methods e.g. Echo Hiding are extremely compression resistant (I've implemented this over a phoneline - it works).

Re: Game of Thrones leak and watermark: a stupid tracking system

#35

Post by jarman » Mon, Apr 13, 2015, 2:10 PM UTC

ipedrazas wrote: post #23

NoMoreNicksLeft wrote: post #5

Not very clever. Get two leaked copies, and mix them up. Use the credits from copy A, or hell, even chop off 11 milliseconds from them. Then mix and match scenes... even chop off a few ms from some randomly selected scenes. I bet you wouldn't even need the two copies.

"Get two leaked copies" Not sure I understand this.

Get two copies from two different sources, with different watermarks

Re: Game of Thrones leak and watermark: a stupid tracking system

#36

Post by est » Mon, Apr 13, 2015, 2:11 PM UTC

fredley wrote: post #2

...or just use steganography. Steganography in videos can be made to be invisible to the naked eye, and extremely robust - even to video compression. It's also difficult to detect, and even more difficult to remove/tamper with. What the author of the article is proposing is actually a kind of steganography, albeit a rather crude one, and probably rather difficult to implement (since scene timings will be different fo…

> and extremely robust - even to video compression. It's also difficult to detect, and even more difficult to remove/tamper with.

Split & merge frame by frame, in random, from multiple video sources. Visually they will be the same, but steganography has a high chance of been broken.

Re: Game of Thrones leak and watermark: a stupid tracking system

#37

Post by edoloughlin » Mon, Apr 13, 2015, 2:11 PM UTC

fredley wrote: post #2

...or just use steganography. Steganography in videos can be made to be invisible to the naked eye, and extremely robust - even to video compression. It's also difficult to detect, and even more difficult to remove/tamper with. What the author of the article is proposing is actually a kind of steganography, albeit a rather crude one, and probably rather difficult to implement (since scene timings will be different fo…

What the author of the article is proposing is actually a kind of steganography, albeit a rather crude one, and probably rather difficult to implement

...but easy to explain (and sell?) to the entertainment industry, who have shown themselves to be mostly technically illiterate. Some cynical, unscrupulous hacker could probably extract a lot of money from them for such a service...

Re: Game of Thrones leak and watermark: a stupid tracking system

#38

Post by joncrocks » Mon, Apr 13, 2015, 2:12 PM UTC

ipedrazas wrote: post #23

NoMoreNicksLeft wrote: post #5

Not very clever. Get two leaked copies, and mix them up. Use the credits from copy A, or hell, even chop off 11 milliseconds from them. Then mix and match scenes... even chop off a few ms from some randomly selected scenes. I bet you wouldn't even need the two copies.

"Get two leaked copies" Not sure I understand this.

I think this means 'gets two copies from sources who have been given their copies legitimately'. Your job is then to make sure that those two people can't be traced/identified by the watermark on/in the video.

Re: Game of Thrones leak and watermark: a stupid tracking system

#39

Post by baq » Mon, Apr 13, 2015, 2:12 PM UTC

NoMoreNicksLeft wrote: post #5

Not very clever. Get two leaked copies, and mix them up. Use the credits from copy A, or hell, even chop off 11 milliseconds from them. Then mix and match scenes... even chop off a few ms from some randomly selected scenes. I bet you wouldn't even need the two copies.

> Get two leaked copies

this should be the biggest obstacle.

Re: Game of Thrones leak and watermark: a stupid tracking system

#40

Post by thefreeman » Mon, Apr 13, 2015, 2:13 PM UTC

Why does the attacker need a second leak? Can they not just randomly clip each scene by a few milliseconds? This would defeat the identification, and not be noticeable to a viewer.