The algorithm uses a special value, called a seed, to identify a group of equivalent serials.
A possible solution to improve this would be to use the bootstrapping feature in Advanced Installer to mask the MSI.
Advanced Installer allows you to easily add a serial number protection for your package.
There are two types of serial validation each having it's advantages and disadvantages: Predefined List and Algorithm Verified.
The seed length and form depend on the length and form of the template.
While the algorithm itself is reasonably hard to crack, the MSI it is not a secure environment.