How to prevent screenshots in a web browser

http://www.patrick-wied.at/blog/image-protection-on-the-web/#/

by bakerfreak • 12 years ago

90 127 12 years ago

EGreg2• 12 years ago

And oncw again if your user is a developer he'd or she'd be able to stitch it back together.

scrollaway3• 12 years ago

That was not the point of the article. In fact, had you read the article, you'd find that your point has been addressed three times over and that the author acknowledges it's all futile anyway.

spaulo12• 12 years ago

But reading the article takes time! People need to comment quickly!

mikeash3• 12 years ago

I don't think he quite does. His conclusion is basically that image protection isn't worth it, because more exposure is better. That's different from declaring it to be futile.

NathanKP• 12 years ago

That demo messed with my eyes. Even though it is interlacing faster than the eye can see for some reason it still felt weird to look at it. Overall, not worth the trouble or the decline in user experience.

mikeash3• 12 years ago

I'm pretty sure it's not interlacing faster than the eye can see, which is the whole problem.

For this to work perfectly, your monitor refresh rate would need to be at least 2x higher than what your eyes can detect. And why would anyone build hardware with such a fast refresh rate?

It's a cute idea, but in the end it ruins the image for normal uses just like the watermarks do.

colanderman2• 12 years ago

Well, the website's down, so I can only speculate, but, how is the website to know the screen's refresh rate? If the site assumes, say, 60 Hz, but the rate is actually 72 Hz, you'll see an odd "fading" effect between the two interlace frames at a rate of 12 Hz, which is very noticeable.

EDIT: Ah, I see he uses window.requestAnimationFrame [1] to sync with the frame rate, so this is not a problem.

[1] https://developer.mozilla.org/en-US/docs/Web/API/window.requ...

gweinberg• 12 years ago

Wouldn't surprise me at all if this technique is seizure inducing.

ChrisClark• 12 years ago

It looks like a flickering interlaced TV screen to me. And, it basically is.

AlyssaRowan4• 12 years ago

Lesson learned: LCD monitors are absolutely horrible at interlacing. And you can, of course, put them back together with one line of JavaScript. As he says, it's futile. People should stop doing this. Yawn.

I am associated with a... certain industry... (ahem) which frequently finds its content reposted (and it wouldn't be right or proper of me to identify any further, but I'm sure it's a moderately generalised problem).

One must be realistic about these things - if we're going to publish things, some people are going to pirate them and that's that. It leaves our control to some degree when we let it loose, regardless of what legal rights we may have. We're going to find them plastered all over Tumblr or TPB or something no matter what we (or Tumblr!) do. That is not necessarily all a negative, especially if it might drive interest and traffic, which may be worth more than any one or two pieces of content for some. If we get enough customers to support ourselves and what we do, that's fine (and we can thank our loyal repeat customers for that; many others are simply not in such a position).

"The invisible wall" might be worth it as a courtesy "please don't save this image" thing, but developer tools exist in browsers, so that really is only a courtesy thing: anything else is a fantasy and nothing else is really workable, but perhaps it presents a sort of reasonable-ish balance, if it doesn't degrade anyone's experience and if people are at least aware we'd prefer that not to happen on balance. I feel the same about any light DRM (for example, for PC gaming, I'd say Steam is fairly "courtesy DRM" compared to its peers, excepting its peers like GOG that have no DRM at all).

(I'm also a reverse-engineer of some experience, so I've found myself analysing others' solutions in other industries quite a lot over the years - it's interesting to look back and see how my own opinions on this matter have evolved from a vehement rejection of any DRM as a matter of principle, to a slightly more nuanced position that it is occasionally not devilspawn but we'd still have a better world without it and anything that may cause users any inconvenience is completely unacceptable.)

Fairly discreet and tasteful watermarking is all we've ever found to be a reasonable solution. What we see when people do repost them, as a result, is more sales - when a few people obviously like what they saw and looked it up. Not a lot, but some. Yay. Have we gained more than we've "lost" (not that we ever had those in the first place)? I don't know, I don't have a crystal ball to guess at events that have never happened, but we've gained some as a result of this, and some is always better than none.

Except those people who edit or crop out the watermarks then reblog them. Fuck those people. That gets right up my nose; there's piracy, and then there's plagiarism, and that's how I interpret that one - it feels like they're taking credit for it (and if they are, that's dangerous: people might think they know what they're doing and get themselves in dangerous situations), or at least they're definitely removing ours, which is irksome particularly when you see a comment thread asking for, as the parlance goes, "sauce" (the source of the content). Those are people who wanted more, dammit, and you cropped out the thing that could have linked them where to get more, and since it's been reposted, they probably don't even know. That's just putting barriers in people's way for no good reason. (Thank you for those few that do reverse image searches in such cases and find us that way anyway, you're heroes. ♥)

Any thoughts?

drz3• 12 years ago

Image search gets you the sauce on any reasonably popular image, so a watermark isn't as critical as you seem to think it is.

If a customer willing to pay for content is really intrigued by your image, he'll find the sauce.

jayrox• 12 years ago

me too, it actually gives me a bit of a headache. almost like when you get used to your work laptop being 60Hz and your home monitor being 120Hz. you can't really see it but you can feel it. nope. don't like it one bit.

GotAnyMegadeth• 12 years ago

I could see it flickering and when I tried to print screen I got the image...

Disclaimer: I only skimmed the artcle

CanSpice• 12 years ago

Clearly the best way is to link to a popular site and have your webserver be overwhelmed by traffic. Can't serve images? Then users can't steal them!

drz3• 12 years ago

Take a few screenshots, until you get one image with the odd lines, and one with the even lines, then stitch them back together in Photoshop.

2 minute job, tops.

Aardwolf• 12 years ago

2 minutes is quite a long time. Long enough to not bother unless you really want that particular image...

programmer_dude• 12 years ago

This can be automated in javascript. There is no need for photoshop. I won't be surprised if someone comes up with a browser extension to neutralize it.

drz3• 12 years ago

Depends on what your hourly rate is, and what they're charging for the image.

For most people (especially the billions in the developing world) it's a good use of their time.

spindritf• 12 years ago

Previously, https://news.ycombinator.com/item?id=8022315

dyeje• 12 years ago

You could still subvert this by taking an actual picture of the screen with a camera I think.

JetSpiegel• 12 years ago

The analog hole. If your eyes can see it, so does a camera.

alexhawdon• 12 years ago

Yup. In audio copy protection this is referred to as the 'analogue hole' (http://en.wikipedia.org/wiki/Analog_hole), and there's pretty much nothing you can do about it.

dsr_• 12 years ago

How to drive away customers: prioritize your unproven loss of income over making an attractive product. Accuse all your users of copyright infringement.

paulhauggis• 12 years ago

I really dislike this attitude on HN. You can have great products that make no money because cracks get popular (I have done testing with my own software and know for sure this is the case) and get higher results than the original product listing on google, Adblock, and many other methods thought to be "rights".

Even look at music piracy. Pirates did the big labels a favor: small, independent artists can't make a living anymore because everyone just expects it to now be free. They now are almost forced to go with a big label if they actually want to make any kind of living.

colechristensen• 12 years ago

Regardless of what you believe I am not going to patronize you if you treat me like a thief, likewise I'm going to fight tooth and nail to ensure that I am the one that controls the device I physically own, not a content business.

meshko2• 12 years ago

Like it or not, you can't do it, so don't waste your time.

kstrauser2• 12 years ago

That attitude is realism. It's not unreasonable to take minor steps to make casual copying easier - the clear GIF overlay is a good example of that - but there ain't no such thing as perfect digital restrictions management. Anything beyond those minor steps becomes an inconvenient nuisance for your real customers and the risk/reward paying just isn't worth it.

Imagine you have a stock photo website. Basically honest potential customers might try right-clicking a photo once to download it, and failing that will whip out their credit card. Basically dishonest non-potential customers aren't going to pay you and see your protections as something fun to be worked around.

There just isn't a business case for heroic measures that can ultimately be trivially defeated.

shmerl15• 12 years ago

independent artists can't make a living anymore because everyone just expects it to now be free.

DRM can't help artists make money. It only helps them lose more.

Examples which talk about it:

* http://www.lexi-alexander.com/blog/2014/6/1/will-the-real-pi...

And this is my favorite part: I am 100% certain that the hacking of entertainment industry's security features provides better entertainment for these kids than the entertainment we're trying to prevent them from stealing. Let that sink in for a second, then try not to bust up laughing.

* http://brutalgamer.com/2012/03/09/cd-project-red-drm-no-long...

Every subsequent game we will never use any DRM anymore, it’s just over-complicating things…We release the game. It’s cracked in two hours, it was no time for Witcher 2. What really surprised me is that the pirates didn’t use the GOG version, which was not protected. They took the SecuROM retail version, cracked it and said ‘we cracked it’ — meanwhile there’s a non-secure version with a simultaneous release. You’d think the GOG version would be the one floating around.”

skizm2• 12 years ago

I don't think anyone is saying piracy is not hurting anyone. To what extent, I would say there is a great deal of disagreement. If a perfect DRM existed (completely prevents privacy while leaving paying customers unaffected) everyone would implement it. However, the message is that you shouldn't stoop to making your own product worse or punish paying customers just to combat piracy. For example, if you're selling software and someone wants to buy it, they shouldn't have to jump through hoops to get it and/or use it. On the other hand if someone wants your product and doesn't want to pay for it, there is a significant probability that is a lost sale regardless of DRM efficiency. Just because a ton of people use a pirated version of your software doesn't mean that a ton of people would have bought it if you had better DRM.

base698• 12 years ago

This is not my experience. I work in a space that is seeing impressive numbers from up and coming acts. To me it seems like the variety and quality of music offered to the consumer has increased leading to more people seeing Joe Blow's act instead of going to Cher or Britney Spears.

All the money is in touring and merchandising.

probably_wrong• 12 years ago

Pirates did the big labels a favor: small, independent artists can't make a living anymore because everyone just expects it to now be free.

This is a point I hear often, but there seems to be no consensus. If I understand you correctly, are you saying that small, independent artists used to make a living just from CD sales?

I've only met in person poor musicians, those that make money either from street concerts or the occasional gig, which were consistent with Courtney Love's position[1] that CD sales are not really important when it comes to revenue. But I'd love to hear an argument from the other side.

[1] http://www.salon.com/2000/06/14/love_7/

the_ancient2• 12 years ago

You may feel it was a "great product" but apparently people were not willing to pay for your great product. Several companies and people get paid giving away their software.

I suspect that your DRM was so overly burdensome that it turned away any potential customers, you in effect screwed yourself.

If the DRM does not get in may way, or require me to do anything(i.e it is invisible to me) then I might buy that software, for example Steam Games, Spotify, etc have DRM that is invisible to the End User. I will grin and bear this level of DRM, begrudgingly. However if you go much beyond this no thank you.

If your software has Activation Keys, Installation Limits, Locks itself to my Motherboard that I change ever 6mos, or other crap like that then you would never get a single dollar from me.

SilasX• 12 years ago

Do you agree that it's sometimes desirable to communicate in a way that doesn't produce a written record? (e.g. insisting that you talk privately in person rather than over email)

If yes, then I think you agree in principle with the goal here, even if you disagree with the specific use case.

jobu• 12 years ago

Obscurity is a far more common problem than plagiarism. The best solution for this is to put a signature in the image. Most people aren't trying to steal an image without attribution, they just want to share something they liked.

stevekemp4• 12 years ago

Most people aren't trying to steal an image without attribution, they just want to share something they liked.

As an amateur photographer you'd be amazed how many people think nothing of taking an image and slapping it on their website, or in their print media.

People routinely use services like imgur.com to rehost images they have no permission to use, and can and will strip watermarks and be silent when asked for attribution.

I'm used to it now, but damn it's frustrating when you take that _one_ great shot and find it everywhere on the internet the next day with no credit.

scrollaway3• 12 years ago

It is unbelievable that the entire comment thread is filled with people saying it's a bad article, it can be worked around, etc, when:

1. The article is an experiment on techniques and what can be achieved.

2. At the VERY BEGINNING of the article, the author links to his own comment in a previous HN post which said "I do not advocate using any of the techniques, please don't use it, it's terrible and will give your users headaches! I'm against ressource "protection" on the web, what's on the internet should be fully consumed by users of it! The article describes just a few experiments I set up to see how far someone could go if it WAS important."

3. The article acknowledges these techniques are ultimately stupid.

What is this attitude? Would you have the same attitude with someone experimenting with XSS flaws, hacks and so on to figure out what is possible? Did you all forget than, in order to do good, you have to know what is bad first?

cookiecaper2• 12 years ago

Totally agree. Articles like this are awesome and ideally HN would be filled with them. It's about a set of interesting hacks, that are ultimately still just hacks, but stimulate the hacker mind and add to an archive that can be drawn upon when/if the reader ever encounters the need to solve a similar problem (hopefully with better practical applicability). Articles like this are amusing, interesting, and inspiring, and embody the spirit of Hacker News.

WorldWideWayne4• 12 years ago

The person you're responding to didn't say "it's a bad article" or that "it can be worked around". I'm guessing that the root comment was simply a reaction to the title. I bet they didn't even read the article. However, you must be aware that the majority of the technical user community hates DRM.

Regarding your points 1, 2 and 3... where does it stop? Should we always be enthusiastic about experimentation for the sake of experimentation? At what point would you say "that's stupid"?

For instance, what if the title was: How To Dump Toxins In Your Local Water Supply

Would you read the article and then come here and congratulate the author on their efforts? I bet most people would glance at the article and then come here and complain about too many toxins in the water and what a jerk the author is.

terminado• 12 years ago

http://www.patrick-wied.at/talks/image-protection/demos/cat....

bsimpson• 12 years ago

That looks terrible in Chrome for Android.

nbush3• 12 years ago

Cool, I love counterintuitive (and even counterproductive) solutions just for their own sake. I tried to do a similar thing with text a while ago: http://nbush.github.io/headache/

awhitty• 12 years ago

This is clever! I think it can be circumvented by removing all spans in a paragraph with more than 1 character.

nbush3• 12 years ago

Thanks! Yeah, there are many JS ways around this, but it would be more than enough to stop most people... including myself in most cases.

fabrixxm• 12 years ago

"Tired of people stealing your content? Looking to make copying HTML text a huge pain for your users? Sick and tired of useful, well-made Python scripts? Headache will make it so users cannot select, copy or paste html text without getting a bunch of garbage as well. Try copying this sentence. No, seriously, try it. Yeah that's right. Now try pasting it somewhere.

Now the only way you can steal my sweet, sweet content is by writing it out letter by letter or writing your own noble script that filters out all the junk. Checkmate.

You might say that this solution is unintuitive, massively inefficient and completely unnecessary. Well that's not the true Hacker Spirit now, is it? " ;)

abbeyj• 12 years ago

As a challenge I wanted to see how hard it would be to circumvent this. Here's a bookmarklet: javascript:void(function(s,i){for(i=0;i<s.length;i++)if(window.getComputedStyle(s[i]).color=='transparent')s[i].style.display='none'}(document.getElementsByTagName('span')))

That should be one line with no spaces if gets line wrapped.

nbush3• 12 years ago

Nice work! Here's another solution posted in an earlier thread: javascript:d=document.createElement("div");d.innerHTML="<style>span:nth-child(odd) {display:none;}</style>";document.body.appendChild(d);

I don't think there's any easy way for the obfuscation to stay ahead of JS reversal. Thanks for taking a look!

shmerl15• 12 years ago

Why would anyone want to do such stupid thing? It would prompt users to bypass it just because. And there are tons of ways to make a series of screenshots or even a video of the screen.

Ksnapshot, imagemagick (import), ffmpeg, avconv etc. etc.

let’s assume things on the web should be protected…

Let's assume DRM is a dumb and nasty idea which always leads to very crooked practices. Period. As if we don't have enough of this EME nonsense.

stcredzero9• 12 years ago

The evidence shows that DRM in the service of corporations and businesses tends to be nasty. But there are reasons to believe that DRM, if used to protect the data and privacy of individuals would be very valuable, with the caveat that it would have to be implemented in a trustworthy way.

What if there was a way to provide access to your medical records to people who need them, only for as long as they need them? What if even the provider of the service couldn't easily circumvent this?

shmerl15• 12 years ago

But there are reasons to believe that DRM, if used to protect the data and privacy of individuals would be very valuable, with the caveat that it would have to be implemented in a trustworthy way.

DRM can not be trustworthy by its mere definition (because trust is a mutual thing, and those who deploy DRM don't trust you - the user. So you have every reason not to trust them in return). And it never can be valuable since it's not only unethical and insulting towards users (since it uses presumption of guilt and police state ideas), but it's also completely ineffective and all it does is punishing paying customers, while the vast majority of actual pirates don't deal with it. DRM should just die out for good.

What if there was a way to provide access to your medical records to people who need them, only for as long as they need them?

Authentication and information security has nothing to do with DRM, even though both can have features like encryption. Let's not mix unrelated subjects.

wavefunction• 12 years ago

That's the same pie-in-the-sky "what if" that loser corps have been pursuing forever. Whatever scheme they come up with, someone else breaks it shortly thereafter, whether it's DiVX, or DVD encryption, or BluRay encryption, or any of that silly bs.

stonogo• 12 years ago

1. You can't.

2. Stop trying.

philjackson• 12 years ago

Read his "Was it all worth it?" section.

kstrauser2• 12 years ago

TL;DR You can't, stop trying. It's not worth the effort, it's tilting at windmills, and it pisses your users off. Just stop.

todd38342• 12 years ago

I am glad that this guy tried. I found some of the techniques pretty clever and I enjoyed reading the article. I do not believe you can stop people from taking screenshots and stealing images but I never considered some of the techniques the author explained. He was much closer to solving this than I expected.

shmerl15• 12 years ago

Instead of that, the author could just talk about why interlacing was used in video in the past. No need to bring any DRM context in the discussion. The tone of the article is what's offending, not the technical details.

enraged_camel• 12 years ago

Yeah, sometimes it is worth taking a shot at problems that are thought to be unsolvable. It helps you gain deep insight into the problem domain and become a better thinker.

wslh• 12 years ago

The answer is simple: you can't prevent (all) users from taking a screenshot in a web browser.

The solution is trivial: launch a VM, make a screenshot, hook APIs such as DirectX, etc.

cousin_it2• 12 years ago

So here's a startup idea that can help with that.

1) Build a library for hiding encrypted information inside images. It should be hard to detect (indistinguishable from random) and robust (e.g. survive printing and scanning).

2) Build a web crawler, coupled with a key store. Crawl the internet for images that contain our encrypted info.

3) The copyright owners will be our paying clients. They will display images only to logged in users, use our service to embed the user information in the image, and deposit the encryption key with us.

4) Whenever the crawler finds a stolen image, we notify the copyright owners and send them the details of the user who leaked it. We don't notify the user, of course.

Right?

rasur• 12 years ago

for hiding encrypted information inside images.

otherwise known as Steganography.

aragot• 12 years ago

I was under the assumption that image/theme services did that already, especially with website themes?

That may be an idea for a copyright troll, btw. Disseminate not-for-commercial-use for free, then charge dozen of thousands of dollars when infringement is found.

AlyssaRowan4• 12 years ago

I gather there was a distinct suggestion that at least one infamous copyright troll had done something like that because the only place their content had ever been found was on The Pirate Bay, uploaded by them, which they subsequently threatened users for downloading.

(You can guess how well that turned out for them.)

AlyssaRowan4• 12 years ago

It seems to me that you've basically described Digimarc®'s business model.

cousin_it2• 12 years ago

Hah! Yes, you're right.

colanderman2• 12 years ago

Blizzard does this: http://www.tomshardware.com/news/watermark-screenshots-World...

AlyssaRowan4• 12 years ago

Sneakily, Blizzard did (does?) that to include an account ID, seemingly so that they could catch people exploiting and then proudly posting screenshots (but editing out their character name).

I've got to hand it to them, that is sneaky, but a bit underhanded. And you could sort of see something was a bit off in screenshots of the more gradiented blue skyboxes (in which it was more visible), but I'd thought that was just a poor JPEG encoding routine, until someone looked closer of course.

breischl• 12 years ago

You could just use TinEye[1], which looks at the actual image data to find copies. I know some artists use it to track down illegal copying, but I'm not sure how accurate and effective it is.

http://services.tineye.com/TinEyeAlerts

skizm2• 12 years ago

I am having trouble with the last demo, I always get the full image when I print screen and then paste to paint. Anyone else?

zobzu• 12 years ago

Its kinda cool even thus of course id never want that on a website.

That said, i took a screenshot on windows 8.1+Firefox and it worked just fine. I took a few more screenshots.... and they were all fine too...

joosters• 12 years ago

It broke my firefox :( First, a popup error message reporting:

SyntaxHighlighter Can't find brush for :jscript

and then the whole browser became unresponsive and needed to be restarted. On the plus side, you've helped Firefox development by discovering a new bug!

Qantourisc• 12 years ago

Also this burns a lot of CPU cycles :(

sidcool• 12 years ago

If someone gets really pissed off, they will just take a pic of their screen with an SLR and then photoshop it.

justbaker• 12 years ago

The title is incredibly misleading..

joeblau• 12 years ago

You're still sending the picture across the network to the screen in your most valiant attempt, but by using the inspector's resources, you can get a url link to the cat image[1]. Like you say at the end of the article, it's not really worth it.

The site being slow is a better deterrent than anything written in the post. 9 Seconds to first byte[2].

[1] http://www.patrick-wied.at/talks/image-protection/demos/cat....

[2] http://www.webpagetest.org/result/140714_WZ_S9F/

spiritplumber• 12 years ago

It took 20 years to get image interoperability down to "solved problem" status, so let's get start from scratch by coming up with something that you have no idea will work on cheap tablets, will eat up CPU on battery powered devices, and makes unwarranted assumptions about display technology! Yay!

MrZongle2• 12 years ago

Ah, the newest form of "disabling right-click on a web page".

Infuriating, bad design then. Still is.

fuzzywalrus• 12 years ago

Anyone else try it?

I was curious and tried his live demo URL. and I used OS X's built in screen capture while using Chrome. The screen capture worked, no special tricks needed. I didn't see any visual degradation between my screen shot and the original.

The long and short of it is his DRM did not work.

jamesgagan• 12 years ago

same here cmd-shift-4 worked fine on both images.

hobbes78• 12 years ago

That also happened to me. But then I realized I set the browser to display everything in 110% by default. If you go back to 100% indeed you can't do a proper screenshot...

miketuritzin• 12 years ago

This article (which I enjoyed) reminded me of a paper [1] I co-authored a long time ago about protecting 3D content using a remote rendering system. The big advantage that we had over 2D content (images) is obviously that we never gave clients a full representation of the protected asset.

[1] http://graphics.stanford.edu/papers/protected/protected.pdf

autokad• 12 years ago

interesting article and method. when viewed from remote desktop, the image always appears interlaced.

otherwise, on a regular screen its barely noticeable. at first glance it looks fine, but then i get the feeling something is off. if i blink or look away quickly, i can see some of the interlacing. but overall, interesting idea of treating the images more as movies rather than images

ZoFreX• 12 years ago

I think maybe you could do this. What about the new, controversial DRM extensions? They're for video, but you could just show a 1 frame video on loop as an image, right?

If those support HDCP then it's encrypted all the way to the display, and it would be challenging to screenshot it.

(Of course, you could take a photo of the screen, but that's a substantial degradation).

drdaeman• 12 years ago

Isn't HDCP broken?

FedRegister• 12 years ago

When will website authors learn that you control the content but the client, by virtue of owning their computer, controls the presentation. At best you can make suggestions. At worse you're at the total mercy of the user.

If you want to give out indelible images then go back to print.

qwerta• 12 years ago

I got more solutions:

1) Ship your own lock-down hardware (tablet) to customers, so they can visit your website

2) Install booths around country which will show your website. No cameras or phones allowed inside!

jastanton• 12 years ago

I did something similar you can demo: http://jastanton.com/experiments/imagescrambler/

Shuffle an image, re-assemble with a bunch of divs with background offset and just the right amount to bring the picture back. If you download the image you get a scrambled imaged.

Doesn't protect against screenshot.

Very fun :)

russelluresti• 12 years ago

So, the demo obviously blinks (at least on my monitor), and the first time I took a screen shot, I got the whole image (though I only got half the second time). So, it doesn't actually work all that well.

But cool write-up, I guess.

snorkel• 12 years ago

Good article explaining some clever techniques. I don't understand all of the whiners here who expected something perfect and foolproof.

Scalar• 12 years ago

I found this fairly clever but pretty impractical. If you put an image online you must assume that it is public domain. The only real way to prevent true theft is to offer a lower quality image but this defeats the purpose of putting your image online in the first place.

Nonetheless there are pretty smart ways to monetize content like this and any professional source will pay to use it.

meshko2• 12 years ago

There is a silly Russian saying which school teachers usually use on that really smart asshole kid in the class -- "a fool got blessed by smart head". Somehow reading this made me think of that. Also think of the environment, how much power will you waste on this useless hack if it were to get wide adoption (not going to happen of course, but _if_)

How to prevent screenshots in a web browser

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