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Questions tagged [copy-protection]

Copy protection or content protection covers various mechanism, such as DRM and software license keys, used to restrict the unauthorized copying or use of software or digital media.

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Short software license keys with asymmetric verification

Would it be possible to implement a modern version of the old software license key scheme that uses an asymmetric signing approach, while keeping the length of the key short, say 40 chars of base64? ...
Larsp's user avatar
  • 23
0 votes
2 answers
609 views

Best cryptographic method to distribute license files

I will describe my problem high-level, and not ask a very specific cryptographic question, since I am open for general suggestions as well. So in my question I will only speak about "security ...
Allgaeuer's user avatar
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0 votes
0 answers
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What is the proper approach to software licensing system? [duplicate]

I am willing to create a server side licensing system for my commercial softwares but not really sure what cryptography method I should be using for best possible security per the standard of modern ...
Farukh's user avatar
  • 101
3 votes
2 answers
360 views

How does PUF hardware help in software activation?

I have read that one of the PUF's application is software licensing, but do not know how. I have been reading different articles and forums (such as here), but still not clear for me. One vague point ...
Shannon's user avatar
  • 263
-2 votes
1 answer
63 views

Are there secure public domain crypto or license management algos? Or are just commercial algos "commercial-grade"? [closed]

Are there secure public domain crypto or license management algos? That is, like a GPL or MIT licensed cryptography algorithm that's as secure or more secure than commercial cryptography? Or are ...
mavavilj's user avatar
2 votes
1 answer
317 views

Activation keys and asymmetric encryption

To me it seems that a quite safe way of creating activation keys is by using asymmetric encryption, so that the end-user could only reverse-engineer the validation method. This way the company keeps ...
Fabi's user avatar
  • 123
1 vote
1 answer
2k views

AES-CBC pre-determined IV vs. null IV

Is there any security advantage to using a pre-determined IV in CBC mode over a null IV? I'm implementing a license key system similar to this article on CodeProject, but I'm confused by the authors ...
Neil's user avatar
  • 21
0 votes
0 answers
745 views

Strategies for securing public key storage on software

I´m kind of new in this so I apologize in advance for any noob mistakes (feel free to point it out) We are developing a licensing mechanism on our software, and I would like some advice. The ...
Fedaykin's user avatar
  • 101
0 votes
1 answer
133 views

How to make a document truly read only

How is it possibile to cryptographically make a document truly read only? As in read only I imply that the user can obviously view it which can be achieved by coding which pixels have which colors. ...
Samuel Allan's user avatar
6 votes
2 answers
1k views

Cryptographically secure product keys

I am looking for a scheme to generate and validate cryptographically secure product keys. My requirements are: Unforgeable. It must be impossible (or at least very hard) for users to forge a product ...
Bill Zissimopoulos's user avatar
-4 votes
1 answer
402 views

Storing the activation status of a product and expire details Android [closed]

In my Android application, it's required to store the activation status of the software and keep track of the activation expire date. What is the best way to store this information? Is it safe to ...
Samantha Withanage's user avatar
4 votes
1 answer
2k views

Can I use SHA1 as license key?

I have recently started looking into creating secure, while not validating against an external server, software product keys. The idea I have had is to create a key consisting of two parts firstly a ...
MindStormer's user avatar
2 votes
2 answers
4k views

Is AES secure for java application licensing?

I have to license a java application and want to code a quick implementation, the scheme I came up with is: The Application calculates a string X which we assume to be the md5 sum of the computer's ...
dendini's user avatar
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3 votes
1 answer
416 views

A situation where security by obscurity might be the best solution - or am I wrong?

Imagine the following situation. There is an application for a microcontroller-driven system. The profits are made from manufacturing and selling the device itself. However, it is expected, that the ...
vsz's user avatar
  • 513
3 votes
2 answers
268 views

One-time token to decrypt a local file

I am trying to achieve the following: Encrypted files are stored on users filesystem. The user uses my client to authenticate against a server. Once he is authenticated successfully he gets a token ...
esskar's user avatar
  • 373
5 votes
2 answers
1k views

Is a RSA-signature of some identifying data a safe way to implement a license key?

I have this idea of implementing a license key: After the user downloads the program, he connects to a website and sends his Windows product ID. The website, then, sends this back to him with a ...
ispiro's user avatar
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10 votes
1 answer
2k views

Advanced Access Content System (AACS) and Subset Difference techniques for Broadcast Encryption

I'm trying to get a grasp on AACS and Subset Difference (archived version with images) for a project I'm working on and am having a hard time coming up with a technically valid layman explanation, let ...
makerofthings7's user avatar
5 votes
3 answers
512 views

Cipher for Product Registration?

I'd like to implement a "Product Registration" scheme into my software where upon initial use, the User must enter a key to unlock it. The key they enter is compared to their encrypted Username. ...
Anti Earth's user avatar