I'm not sure what laws apply to you where you live so you'd have to check, but you could also do this on pen and paper if that helps :)
What I've heard about the DMCA, they will even throw you in jail if you crack the calculation in your head. Without telling anyone or writing it down. ;)
What I've heard about the DMCA, they will even throw you in jail if you crack the calculation in your head. Without telling anyone or writing it down. ;)