hi expert
i wrote desktop application

i want to insert it on the internet free for 30 days

after 30days i want to any one who want my app contact me and purchase my app

i need some idea for protecting my app from cracking,

thank's

It sounds to me like you are looking for a licensing mechanism.
There are a number of approaches to this, and one common way is to tie each license to a physical machine. When the customer decides to buy your software, they contact you with and send some data that your software gathers about their machine (such as NIC card id and hard drive id, and so on). You generate a license key based on their machine info hashed with a key that you provide.

Anyway - if you search google or msn for ".NET Licensing Schemes" you'll find enough reading to put you to sleep.

Woody Z
http://www.learntoprogramnow.com
How to use a forum to help solve problems

hi,

thank's for your suggestion

i'm scholar
i study computer

for my final project i will work on security in applications

but i dont know start from where?

can you help me in this topic too?

onece again i thank's for your help(s)

best regards

This is a big topic - but you can get a lot of very good information via the web doing a google search as I stated in my earlier post. That search is where you start. Once you have a basic understanding of what is typically done, if you have specific questions then I would be happy to try to answer. There will be many others here who will be able to also help.

Woody Z
http://www.learntoprogramnow.com
How to use a forum to help solve problems

hi
thank you

can you tell me some site for this topics?

i like to have your yahoo id for chat and for talk about .net and ect

my name az mahdi and my yahoo id is royaye.mahtabi

thank you