how to secure my windows application in C# from piracy without using database?

I am developing a windows application for my client, in .NET Framework 3.5, using C#. There is no need of any database in my application.

I want to secure my applicatio开发者_如何学编程n by making a registration process at the time of installation, where the user will be asked to enter a registration key, which should be machine dependent, otherwise the user can copy the installation folder and distribute to others, which i don't want to happen.

Please suggest me, how to achieve this.

Thanks, Bibhu

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I believe you will need a registration service.

• When the user registers (they'll need to be online), their registration 'code' is sent to your registration service along with their machine details / other identification (username?).

• Your service verifies this & returns a key which can be decrypted by your app using their machine details / identification. Your service also marks that registration code as 'used' so that no one else can get a valid key by using it.

• The application stores the valid key in registry, or even config. It won't work on another machine because it is specific to the machine details.

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my suggestion is this ways:

1)you can create a registery key after registration and in start up of your app check this registery key.

2)you can create a web service (over local network or internet) and on startup check if this version is registerd or not

3)create a custom file and store a hashed value based on machine and in startup of you app check this file

in every 3 way do not forget OBFUSCATION

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There is no way to guarantee software is secure. Even registering over a network can be faked with the use of packet analyzers. In securing software, all you can do is make it slightly inconvenient for professionals, difficult for dabblers, and impossible for people with no knowledge. Generally, it's accepted that obfuscation is not a good protection, because someone will eventually figure it out and publish it anyway.

Also keep in mind that the more secure you make your program, the less usable legitimate users are likely to find it. It's a hard balance to strike between usability, security, and the value of what you lose if security is broken. There is no hard and fast 'right' way to secure something.

For machine dependent information, you can gather information about the hardware on that system, hash it somehow, and store the value somewhere, and then check it at the launch of the program each time. It's not fool-proof, but it allows some security fairly easily.