license key verification in C#

Question

hi all

i am working with desktop application

when i install my setup one license key is required for this setup

i am randomly generating this 16 character license key

can you tell how to verify this at the time of installation

i want such type of code to verify this key

or whole code how to generate this license key and verify this key

please help me its urgent

thanks in advance   

i am waiting for your valuable help

Answer 1

hi,

i am working on desktop application

i want such type of algorithm which is use to validate any key that is enterd by user when he install the setup

when we install my  setup this setup want a license key this is entered into four textboxes each textbox can have four character means length of key will be 16 now i want to validate this key

first i am converting this 16 character key into binary no

i want such type of algo that return same result for every key

jukt like that first license key convert into binary form this binary form pass this algo abd this algo return zero or any thing else whatever you want  

  and sum or multiplication or division

Answer 2

Dim SerialNumber = Guid.NewGuid 

Var SerialNumber = Guid.NewGuid();

Try this next time in the forum for the program language you are using. 

http://social.msdn.microsoft.com/Forums/en-US/vbgeneral

http://social.msdn.microsoft.com/Forums/en-US/csharpgeneral

This is a forum for the System.Windows.Forms namespace and related questions for that but at least containing elements of that namespace.

Be aware some use this namespace also with C++ managed or F#

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Success
Cor

Answer 3

http://www.codeproject.com/KB/security/cdkeys.aspx

http://www.codeproject.com/KB/install/LicenseKeyGeneration.aspx

http://www.codeproject.com/KB/install/VB_KeyCode.aspx

Kindly have a look at the samples provided in the above link

Regards,

Narendran Ponpandiyan

Answer 4

You would find apt answer in another thread

http://social.msdn.microsoft.com/forums/en-us/winforms/thread/9B8F74F2-290A-4AEF-AE1E-12E430263B82

Hope this helps.

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Please mark this as "Answer" or "Vote as helpful" if it has resolved your issue/question/problem.

Answer 5

 

If you use Visual Studio Setup and Deployment projects, you might already know that it is not very good for creating really smart setups we often need. I'd like to share two alternative ways to create installers within Visual Studio IDE:

+ Lexpa - Inno Setup integration for Visual Studio [http://www.lexpa.com]. Creates small and fast installers.

+ Votive - WiX toolset integration for Visual Studio [http://wix.sourceforge.net/votive.html]. Creates MSI-based installers.

Both add special project type to VS Add New Project dialog and allow you to create setup of any level of difficulty.

Or:

http://www.oreans.com/winlicense.php

http://www.interactive-studios.net/products/qlm.htm

 

http://stackoverflow.com/questions/453030/how-can-i-create-a-product-key-for-my-c-app

 

You can do something like create a record which contains the data you want to authenticate to the application. This could include anything you want - e.g. program features to enable, expiry date, name of the user (if you want to bind it to a user). Then encrypt that using some crypto algorithm with a fixed key or hash it. Then you just verify it within your program. One way to distribute the license file (on windows) is to provide it as a file which updates the registry (saves the user having to type it).

Beware of false sense of security though - sooner or later someone will simply patch your program to skip that check, and distribute the patched version. Or, they will work out a key that passes all checks and distribute that, or backdate the clock, etc. It doesn't matter how convoluted you make your scheme, anything you do for this will ultimately be security through obscurity and they will always be able to this. Even if they can't someone will, and will distribute the hacked version. Same applies even if you supply a dongle - if someone wants to, they can patch out the check for that too. Digitally signing your code won't help, they can remove that signature, or resign it.

You can complicate matters a bit by using techniques to prevent the program running in a debugger etc, but even this is not bullet proof. So you should just make it difficult enough that an honest user will not forget to pay. Also be very careful that your scheme does not become obtrusive to paying users - it's better to have some ripped off copies than for your paying customers not to be able to use what they have paid for.

Another option is to have an online check - just provide the user with a unique ID, and check online as to what capabilities that ID should have, and cache it for some period. All the same caveats apply though - people can get round anything like this.

Consider also the support costs of having to deal with users who have forgotten their key, etc.

 

 

Or you can try Shareware Starter Kit:

http://blogs.msdn.com/b/danielfe/archive/2005/07/10/437293.aspx

http://social.msdn.microsoft.com/forums/en-US/Vsexpressvb/thread/39a42b89-f312-4e15-b218-34e4e1617733/

 

Or the Serial Key Maker:

http://www.serialkeymaker.com/how_to_implement_serial_key_maker.aspx

 

There're also several links would be helpful to you:

http://www.debugging.com/bug/16115

http://www.codeproject.com/Answers/159167/csharp-Setup-for-Trial-and-Serial-key.aspx#answer3

http://www.codeproject.com/KB/install/LicenseKeyGeneration.aspx

http://www.emoreau.com/Entries/Articles/2007/12/Licensing-a-VBNet-application.aspx

 

As I mentioned, visual studio built in deployment technical is not suitable for you to request a smart installation package. And the option is according the above information to use others product, rather than research the setup project option.

 

Or if you also want to do this hard work with visual studio setup project or yourself, you can ref the following several articles:

http://www.indigorose.com/webhelp/sufwi/HowTo/Add_a_Serial_Number_Validation_Screen_to_Your_Project.htm

http://helpful-tech-how-to-tips.blogspot.com/2010/05/how-to-validate-serial-number-during.html

http://www.codeproject.com/KB/security/NbbfArchitecture.aspx

 

incorporating-license-key-approach-for-a-winforms-app

algorithm-for-unique-cd-key-generation-with-validation

how-to-generate-and-validate-a-software-license-key

Crypto Primer: Understanding encryption, public/private key, signatures and certificates

 

 

And for other deployment solution(exclude the visual studio setup project and ClickOnce), you can go to their special forum for more expert help to help you achieve your goal easier.

You can find most of the deployment solution products and their website(forums) form this url:

http://installsite.org/pages/en/msi/authoring.htm

 

For more discussions on this topic, you also can ref the following thread saying:

http://social.msdn.microsoft.com/Forums/zh/winformssetup/thread/301913a0-ecf9-4095-8d66-a3f4baeea6eb

 

Or the easier way is put the validate processes in the application start proceeds, then you can ensure the key every time or the first time you boot the application.

 

 

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Mike [MSFT]
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Answer 6

Aren't you actually associated with SoftActivate, Catalin?