Question: How can I create a product key for my C# Application?

I need to create a product (or license) key that I update annually. Additionally I need to create one for trial versions.

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> Related:
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> * [How do I best obfuscate my C# product license verification code?](https://stackoverflow.com/questions/501988)
> * [How do you protect your software from illegal distribution?](https://stackoverflow.com/questions/109997)
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Answer: 
Whether it's trivial or hard to crack, I'm not sure that it really makes much of a difference. 

The likelihood of your app being cracked is far more proportional to its usefulness rather than the strength of the product key handling. 

Personally, I think there are two classes of user. Those who pay. Those who don't. The ones that do will likely do so with even the most trivial protection. Those who don't will wait for a crack or look elsewhere. Either way, it won't get you any more money.
Another good inexpensive tool for product keys and activations is a product called InstallKey. Take a look at [www.lomacons.com](http://www.lomacons.com)