>Then, how a software like crypkey is really sure that it can do that? I mean protecting the siftware from being executed twice? or others like Aspact. I have never bought it but in the demo, users can put his exe/setup files according to the protections available in the program such as numbers of executions, number of days and serial number. I am wondering whether the full version of Aspact can do it if you say that it is impossible. So what is the difference between protecting softeare from being copied or installed twice and a cd of movie from copied illegally.Why is those software companies are really confident?
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>Regards
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>Syah N

Your question was whether it was possible to protect a program to be copied, and that is simply impossible, unless you do something to the hardware.

To protect the program from being run on more than one machine, is a completely different matter. My own company uses a system where the software needs a serial number, and the serial number is created specifically for each customer. The customers gives us some information, and we send the custom made serial number. When the serial number is entered the first time, we register some keys in the registry, and a few files are created. On startup, the registry keys and the files are checked. We also hardcode the customers name on all printouts, so if someone managed to "crack" the protection, the software will be of little value since they then would need to change the customers name. Since the serial number includes a checksum for the customers value, a change in the customers name would make the program not start.