Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Game of Thrones leak and watermark: a stupid tracking system

blog.frite-camembert.net

Post reply on HN
Print view View original

111–120 of 286 posts

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

#111

Post by VeejayRampay »

selectout wrote: post #100
robertwalsh0 wrote: post #74

Was talking to my partner about this and she had a pretty clever take: "Seems like a simple idea would simply be to change just the spelling of one seemingly insignificant name near the end of each version of the credits and then by actually watching the credits you'd know the leaker straight away." "Of course, you'd leave the watermark on there so the leaker doesn't know how you caught them and thinks that the water…

Unsure how the credits work for Game of Thrones, but if it's like most shows where it's just the rolling black screen at the end of the show then most torrents cut that part off entirely by default.

Still waiting for some clever chap to cut the opening out as well. The dream would be to have one version of the opening and a mencoder script to put the pieces back together. It would shave a few dozens megabytes on each file off.

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

#112

Post by TazeTSchnitzel »

sxp wrote: post #97

What happened to the site? http://blog.frite-camembert.net/got-leak.html Now shows a generic 404 and http://blog.frite-camembert.net/ shows a github 404. Was the information DMCA'd?

Still works for me.

Also, the author seems to know nothing of steganography so HBO haven't had anything of consequence discovered by them.

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

#114

Post by TazeTSchnitzel »

themoonbus wrote: post #96
robertwalsh0 wrote: post #74

Was talking to my partner about this and she had a pretty clever take: "Seems like a simple idea would simply be to change just the spelling of one seemingly insignificant name near the end of each version of the credits and then by actually watching the credits you'd know the leaker straight away." "Of course, you'd leave the watermark on there so the leaker doesn't know how you caught them and thinks that the water…

Or, just add an insignificant name (changing someone's name might run you afoul of contracts, even in a review copy).

Add a series of random names in the middle of Special Thanks. The names are in a list stored somewhere, so are actually (large base) digits of a serial number.

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

#115

Post by TazeTSchnitzel »

krob wrote: post #80

Everyone in her claims that there are mechanisms to add non-visual watermarks into both video & audio, anyone have any suggestions as to what products / systems to use so this can be implemented? Minus writing one yourself (like writing your own framework, you don't know all the gotcha's of an expert)

It's not a very compression-resistant approach and more sophisticated methods are usually used, but a simple one is using the low bits of colour channels. In a red pixel you have bits like so:

  RED      GREEN    BLUE
  11111111 00000000 00000000
A change in the most significant bit of any of these colours would be massive. 01111111 is half as bright as 11111111.

But a change in the least significant bit(s) is barely noticeable. You probably wouldn't notice the difference between 11111111 and 11111110, especially as you don't experience individual colour channels, you see a blended colour. And when you're looking at something with thousands of pixels you simply won't spot it.

So, stick your secret message in the low bits:

  RED      GREEN    BLUE
  11111XXX 00000XXX 00000XXX
You now get 9 bits of data per pixel. Or less (for a less noisy image) or more (for a more noisy image). For a 640x480 image, you now have 345.6KB of data. And if you use encrypted data, it won't even seem like data if someone looks (plausible deniability). Just noise.

Techniques like this were used on 4chan to hide child porn in high-resolution photographs. This the "mods are asleep, post hi-res" meme.

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

#116

Post by plorg »

Even with a blurred watermark, the mark itself could be enough to pinpoint a source. At least if the watermark disappears and reappears several times in a video you could use the timestamps of its appearance and disappearance to indicate who was responsible for a leak.

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

#117

Post by bru »

sxp wrote: post #97

What happened to the site? http://blog.frite-camembert.net/got-leak.html Now shows a generic 404 and http://blog.frite-camembert.net/ shows a github 404. Was the information DMCA'd?

It's hosted on github pages and I inadvertently deleted the CNAME file when updating the post: https://github.com/brunal/brunal.github.io/commit/89fd81f93d...

It took me ~20 minutes to realize it was gone, you probably tried to hit the page during that time frame.

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

#118

Post by Strilanc »

royjacobs wrote: post #48
est wrote: post #36

Earlier quoted context omitted.

> 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.

Any steganography solution on the market today that is worth its salt would actually be robust against this. The amount of different sources you would have to combine to protect against this is higher than you'd realistically be able to find. Disclaimer: I used to work at one of the leading companies in this field.

That's very interesting. I always assumed averaging (maybe with varying weights across frames and time), or applying a few rounds of other steganography, would degrade the encoded message into noise.

Could you link to some papers? If you try to encode lots and lots of messages with different keys into the video, does it ruin the quality before ruining previous messages?

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

#119

Post by queuedvariable »

oldmanjay wrote: post #82
est wrote: post #36

Earlier quoted context omitted.

> 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.

it's amusing to me, how much effort people are willing to put in to get free entertainment.

Even better? Those of us who do it all after paying for the service.

Sometimes, it's not about the money.

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

#120

Post by forrestthewoods »

This is a stupid blog post. There are two goals:

1) Prevent copies from being leaked 2) Trace leaks if they happen

Watermarks are actually great for the first goal. They are big, ugly, and obvious. This discourages people from leaking. If they do leak it's crystal clear they're taking a huge risk. This is also why the DVD screener is low-res SD.

HBO already tracked down where the leak came from. Whatever methods they have in place to do so were successful. Thus any complains about watermarks being ineffective at goal #2 are irrelevant.

Post reply on HN