The encryption keys are hidden within the code in such a way that even if you see the algorithm, you cannot easily extract the key. Breaking this requires symbolic execution and is beyond basic cracking.
Modern software has evolved. The “practicals” that worked on 2005-era shareware fail against: cracking software practicals csp install
Assuming you have your Virtual Machine running (e.g., Kali Linux or a standard Windows 10 VM for specific Windows-based tools), here is the practical workflow for installing these exercises: The encryption keys are hidden within the code