How to add license functionality in my VB.NET application

I am using VB.NET for coding and SQL Server 2005 for database.

My application is ready for release. Just on thing missing before I can go live.

I want to implement license concept in my application.

My license file can be text or xml file. In which there should be some encrypted matter which will be used for validate the application.

Please suggest how I can implement this functionality in my application

Thanks.

Best 开发者_开发问答Regards, Solution