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96 votes
Accepted

Discouraging users from copying images off a website?

There is no way to block saving of images, but here are some ideas to make it harder. To prevent right-clicking the image to save it, you can overlay a transparent div on it. The user will then right-...
Sjoerd's user avatar
  • 31.5k
62 votes

Schemes/ Mechanisms that could provide one time decryption?

There is no way to do this - this is a subset of what DRM schemes attempt to do. If an end user can decrypt something once to see it, they can see it again. Any of the following may be possible: ...
Rory Alsop's user avatar
  • 61.5k
40 votes

Is it possible to embed information that is both nearly invisible to the naked eye and decodable from an external camera?

Consider that you might not want what you are asking for. That is, if the purpose of watermarking is to prove that you authored it, your cuttingroom clips and outtakes are evidence enough - you can ...
Dewi Morgan's user avatar
  • 1,429
36 votes
Accepted

Is it possible to embed information that is both nearly invisible to the naked eye and decodable from an external camera?

Your use case calls for a robust watermarking scheme. It has to resists compression and uncompression of the image, has to resist modification (e.g. white balance changes, lost pixels) and also ...
M'vy's user avatar
  • 13.1k
31 votes
Accepted

Is it impossible to protect an API from data redistribution?

It's not something you can do with technology. As soon as the data leaves your server, it isn't your data anymore. There are several ways a malicious user can extract data from your application: ...
ThoriumBR's user avatar
  • 54.5k
25 votes

Schemes/ Mechanisms that could provide one time decryption?

As you already hinted at, such a thing is only possible in hardware. A software or encrypted data solution would always suffer from the option of making a copy before decryption. In hardware, the ...
Tom's user avatar
  • 10.4k
23 votes

How difficult is it to intercept the POST response body when SSL is used?

It all depends on the application itself and what kind of security measures are implemented. Assuming requests are sent over HTTP(s), then the easiest way is to use a proxy such as Burp. You will need ...
HamZa's user avatar
  • 1,361
22 votes

How to use FDE without needing to share the encryption password

It comes to this: You want to implement a DRM scheme. Many before you have tried, all of them failed. It is not possible to give something (hardware, data) to users and prevent them from using it in ...
Josef's user avatar
  • 5,963
21 votes

Discouraging users from copying images off a website?

Before doing things like this you always have to ask yourself: What is your actual goal? It is impossible to stop a determined attacker from getting your images, what you can do is make it harder ...
Voo's user avatar
  • 670
21 votes

Is it impossible to protect an API from data redistribution?

This is a classical Digital Rights Management (DRM) problem. There are no definite solutions, not even in your particular scenario. DRM techniques can make it more difficult to distribute data, but ...
Ja1024's user avatar
  • 10k
19 votes
Accepted

How to use FDE without needing to share the encryption password

According to my previous answer, suggestion by @logneck and a bit of google-fu, I came to the conclusion that it is possible to implement the scheme requested in the question with available tools and ...
usr-local-ΕΨΗΕΛΩΝ's user avatar
17 votes
Accepted

Displaying on screen without being recordable by another app

It's an OS / driver-level function, yes. The screen recorder app isn't literally recording the screen, obviously - for that it would need hardware either in the display or in front of it - so what it'...
CBHacking's user avatar
  • 49.3k
15 votes

How to prevent illegal file transfer or copying of video files from a PC?

As you state in the question, doing this in a foolproof way is technically impossible. For the video to be displayed on the screen it must somehow reside somewhere in the RAM on the computer, be ...
Anders's user avatar
  • 65.6k
12 votes

How to prevent illegal file transfer or copying of video files from a PC?

Do not roll your own DRM scheme. The industry have tried and failed so many times that a homebrew solution will stand little chance. It would be better to "stand on the shoulders of giants" and use ...
billc.cn's user avatar
  • 3,946
11 votes

Discouraging users from copying images off a website?

I've been faced with that problem several times. The best solution we found was to drastically reduce the image quality. Make it acceptable for the screen but too low quality to print out - even if it'...
Mayo's user avatar
  • 296
11 votes

Discouraging users from copying images off a website?

There is nothing you do which makes it impossible for users to view the content without being able to save it. The best you can manage is to make it more difficult. And if you make it more difficult ...
symcbean's user avatar
  • 18.7k
11 votes
Accepted

Encrypt folder on Linux that can only be decrypted on that specific OS and device

No matter what you do, you will need to store an encryption key somewhere, which will then be recoverable. If you require a license server, this could be worked around by hooking or patching the ...
multithr3at3d's user avatar
10 votes

Schemes/ Mechanisms that could provide one time decryption?

If a network is available, you could offload the decryption procedure (and the private key) to a service running on a secure server. You could then enforce whatever rules you want on the server. The ...
John Wu's user avatar
  • 9,321
8 votes

Discouraging users from copying images off a website?

Consider that an comic artist's business model is fandom. They make money by having fans*. Not so much because of the sales: sales happen because they have fans willing to pay. As such, limiting ...
joojaa's user avatar
  • 485
8 votes

How does HDMI splitter bypass HDCP?

HDCP has a built-in failure mode when it communicates with a device which doesn't support it: it downgrades the video content to standard definition (or sometimes 720p). The video splitter "trick" ...
Polynomial's user avatar
  • 135k
8 votes

How to put executable code in files?

The field that you're nibbling at is called Digital Rights Management (DRM), and it's a big field. Protecting your documents and music, for example, fall under Content Restrictions. There are ...
gowenfawr's user avatar
  • 72.9k
7 votes
Accepted

What protects HDCP keys in software?

What prevents an attacker from reverse engineering the player software and using the (valid) keys or the oracle access to make illegal (high-quality) media copies? There is nothing which fully ...
Steffen Ullrich's user avatar
7 votes

How to prevent illegal file transfer or copying of video files from a PC?

As mentioned, its impossible to prevent capture of the displayed video - even in the worst case, the user can record the video on a smartphone or using a fixed camera (as some pirate movies do when ...
gbjbaanb's user avatar
  • 218
7 votes

Discouraging users from copying images off a website?

I'm surprised no-one has mentioned Digimarc or the EURion Constellation yet. Digimarc Digimarc is a human-imperceivable digital watermark that embeds authorship information into a raster image. ...
Dai's user avatar
  • 1,728
7 votes

A file that doesn't allow copy/paste or print

Nope, and it can't exist in the general case, because you don't control the client device. This is essentially the problem that DRM solutions try to solve for video and audio content, and text or ...
Matthew's user avatar
  • 27.4k
7 votes

How does Widevine, FairPlay, and other DRM's work under the hood?

If the above is the case, I assume that an attacker could simply edit the binary for the CDM to access the key or the file after is decrypted. That's why a lot of DRM systems are not implemented on ...
binarym's user avatar
  • 784
6 votes

Discouraging users from copying images off a website?

Well, i've tackles this a few times. It's impossible to stop. I can bypass all these measures in 2 seconds, but they would scare me off because of the doubt if you are serious about persecuting. Use ...
Tschallacka's user avatar

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