However, the specific combination of terms — "password recovery" plus "registration code" — also highlights ethical and security concerns. Password-recovery tools can be powerful: they may employ brute-force, dictionary, or cryptanalytic techniques to reveal workbook passwords. That capability can be used for lawful recovery (a user who legitimately lost access to their own file) but also for misuse (accessing others’ protected data without authorization). A registration code for such a tool must therefore be treated with care: sharing or obtaining codes through unauthorized channels undermines licensing models and may facilitate abuse.