Encrypt file (.licence) + verification?

[TipGiver]

Hello,
Imagive the next:

I want my app when it loads to use a .licence file (it's just an extension). It should contain 3 strings like: 2006 string1 string2. These are very important because they are used in printing and in database.
(Specifically, the year locates and completes the path to the database, after being created - if necessary.)

So, if a user open the file, I dont care if he can recognize the data, but i dont want to be able to change them. I am not sure if this technique is called hashing, but either way or not, i need help on this.

To conclude, the app should not load if the validation of the .licence file fails. If it succeeds, then i will save these strings in variables for further use in the application.


Thanks on any guidance!

 

[SHelton]

Have a look at

http://jclement.ca/devel/dotnet/reallysimplelicensing.html

 

[TipGiver]

thanks, i'll give it a try and post again!

 

[TipGiver]

I have a question on this.

In Licence.cs file and in the routine 'License' (i think it is the constructor) there is:

key.FromXmlString(m_pubKeyString);

The declaration of 'm_pubKeyString' is:

private const string m_pubKeyString="[b]<RSAKeyValue><Modulus>[/b]vNcK8QuQA78kCez+Mc2gvtNuQP1nNYlT7BveNKKoFQ+WSERV7jh" +
						 "KTEKoBt/KFsY8tOVRNiPfNud/x9zzwA+lGgTHUlpSfKi7kOc5HHCxKcHk+GB35hBU19QnSQwA" + 
		                 "1YiLK3tNMWQ3OjKE1oMNa3FmRJpGu97hAEZexswz+/sbpq0=[b]</Modulus><Exponent>[/b]AQAB[b]<" + 
		                 "/Exponent></RSAKeyValue>[/b]";

The bold XML tags... what are they for?

 

[SHelton]

I can't pretend to be knowledgeable on cryptography, but there is a decent article which explains cryptography in .NET here:

http://www.devx.com/codemag/Article/16747