Hot answers tagged

76

No, there's no way to do it. Without setting connection parameter limits, there's even no way to make it relatively difficult. If a legitimate user can access your website, they can copy its contents, and if they can do it normally with a browser, then they can script it. You might setup User-Agent restrictions, cookie validation, maximum connections, and ...


53

What you are trying to do is futile. Information can not be contained. You can not prevent someone from passing on information. When they can not share their logins, they just copy&paste the text. When you disable copy&pasting (the common methods to do this can be easily bypassed, by the way), they will make screenshots. When you find some way to ...


46

As far as I know there is no feature like that in Adobe Reader. But even when there were such a feature, it couldn't be effective. PDF is an open format, so they could just use another PDF-capable program to view it which doesn't support this feature They could create a copy of the file before opening it. Adobe Reader couldn't know about that second copy, ...


36

In addition to the existing answers, I just want to stress out that cookies are not meant to be a reliable persistent storage. They can be cleared on many occasions without asking user's consent, for example after a browser crash, an upgrade, profile corruption, you name it. You cannot just issue a fair warning to your users and expect them to keep the ...


29

DRM works pretty well for anything that you do not hand out to the users. Let's take Second Life as example. Second life is an 3d online game in which avatars are rather simple on their own in the sense that they cannot do anything beside moving around and using objects. Objects consists of a shape and texture, and they may contain scripts. Those scripts ...


25

Protect the part of the site you want to protect with a username and password. Then only assign a username and password to people who sign an NDA, (or similar) that says they won't extract or copy information from your site. Another trick is to make all your content load from AJAX... and make the AJAX data URL load from paths that change (such as ...


25

As has @Adnan already pointed out in his answer, there is really no way of stopping a determined person from copying snapshots of your website. I used the word snapshots here, because that's what such content scrapers (or harvesters) are really copying. They don't (or at least shouldn't) have access to your backend where your website contents are actually ...


25

There is a way to distribute the risk such that any single print-shop gains no benefit from copying your files: Visual Cryptography. But it is esoteric and it is hard-core - versus simply buying your own printer or eBook reader. To print PDFs at untrusted print-shops with visual cryptography, you use special software to split each page into two parts - ...


22

According to the E-book A survey of complex object technologies for digital libraries, DigiBox seems to be a container format that can contain different file types (although it was mostly used for PDFs). The basic concepts here are: The file is encrypted in a way that it's relatively difficult to read without special software (i.e you can't just read these ...


20

There's no technical way to solve this. The file (or, rather, a version of it) will be stored in the computer's cache for some time, and sent to the printer which will keep it there for some time. There are several places where a version of your file can be intercepted and stored. If you don't trust the copy shop, get your own printer.


19

Back then, tapes were just binary data on a magnetic film, with no "hidden" channels or out-of-band capabilities. Manufacturers that claimed to make tape-to-tape recording impossible often just made the tape look different, to deter would-be pirates. A regular tape recorder module was usually used to read them, so making "special" tapes couldn't really work. ...


19

The license generation method isn't really that important, as long as it's non-trivial. The trick is how your client verifies that the license is correct. Let's say you do something like this: BOOL verifyLicense (char* licenseKey) { BOOL result = false; if(strlen(licenseKey) > 128) return false; char* url = (char*)malloc(1024); ...


16

For digital restriction management to be effective, it needs to be a sealed hardware implementation the user can not tamper with without destroying the hardware (like a TPM). Software-based DRM implementations can only work on the user-interface level. A compliant software will just not show the user interface elements necessary to perform the restricted ...


15

Everything the human user sees, he can record. As @Adnan points out, this is rather easy, and can be automated. However, some sites still have some relative success at deterring mass slurping. Consider, for instance, Google Maps. Many people have, occasionally, tried to recover high-definition maps of large areas through scripting. Some have succeeded, but ...


14

One tool for trying to enforce DRM is watermarking, i.e. embedding within the media itself a mark which is (almost) invisible to the human viewer, but which is resilient to copies (i.e. the copy has it). Once media copies are individually marked with the identity of their rightful owner, you can trace the origin of fraudulent copies. Do not get it wrong: it ...


13

Convenience: Offering good codecs NOT Preventing DVD players from fast forwarding through FBI warnings and 15 minutes of marketing Easy distribution: kindle, itunes, etc Allowing fair use: CSS (DMCA), moving between devices, no region locks, etc Reasonable pricing for electronic goods If there is more value in buying the good then downloading from ...


13

On a general basis, proactive measures do not work. For instance, your "specific reading application" is defeated by using virtualization: the guest operating system and its applications (including your reading application) believe that they have full control of the machine, but the machine is not a real one, and the host can easily keep screenshots at will. ...


12

If I recall correctly, some games even managed to defeat direct tape-to-tape copying. In principle, this couldn't be possible, as the audio track on the tape contained all the information required. In practice, by using a custom loader which operated on data files encoded at a higher frequency than the standard Spectrum data files, low-quality ...


12

Setting aside the fact that this is futile, which has already been established, there is an additional avenue that could be considered: compulsory two-factor auth. If you require each login account to register a 2FA token (Google Authenticator, etc.) or to simply click a verification link that was sent through a side channel if it looks like they are a ...


9

when DRM-protected material is encrypted using the AES cipher DRM solutions try to allow playback of the media, while not allowing to create a copy. To make playback possible with current hardware the media either has to decrypted at the local host or it has to be provided in decrypted form already. In the second case no decryption is needed while in ...


8

How does the key-system work? Well it depends there are many implementations. One of them was discussed in stackoverflow: Assuming you don't want to do a special build for each user, then: Generate yourself a secret key for the product Take the user's name Concatentate the users name and the secret key and hash with (for example) SHA1 Unpack the SHA1 ...


8

One possible model for preventing software piracy is Trusted Computing. The hardware platform is "trusted" in that it should be tamper resistant and will refuse to run non-authorized code, or divulge the contents of the RAM. This is the model employed by game consoles, e.g. the PS3. This relies quite heavily on symmetric encryption (so that important code ...


8

There is no cryptography in there. It is all a matter of state. The application can access the system time, also the hardware clock (that's the clock with a battery which keeps time when the computer is off). The application can also look at the modification dates of various files to try to detect foul play with the system clock; and it can measure elapsed ...


8

In general, this is impossible. Anything your users can access, they can create an insecure copy of. That said, this is a problem that people have tried to solve before, and they have come up with some partially effective methods (see iBook or Amazon Kindle, as vcsjones suggested in a comment). These methods rely in part on punishing violators, so that ...


7

There isn't a technological answer as once you let someone view your content on a device in their possession, a tech-savvy person can and will get at the images if they want them. At best, you could make it more difficult than its worth; e.g., send a user the images on a locked-down tablet/image viewer with no networking/data out cables. (So if they want ...


7

How much protection do you really want ? The problem is that when the image reaches the client's computer, it's not yours anymore. The specific image that is displayed in his computer can be captured and can be used anywhere, if protected by software. So, if you really don't want that the picture is redistributed and used, you can't send him the image. What ...


7

Those good old days. When I was young I copied some Spectrum games and had to work my way around copy preventions schemes. Tape-to-tape copying is described in other answers. I was interested in digital copies for the best results. Data on the tape in standard format was essentially just a series of bytes. With a few standard statements (LOAD, SAVE) you ...


7

This method is called Audio Watermarking and it's around for a while. It's not as easy to use/implement as you think, and it's not very effective. If you want to try, I can sugest two sites with some information on methods to watermark mp3 files.



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