▁players ▁in ▁any ▁open ▁source ▁operating ▁systems , ▁since ▁open ▁source ▁player ▁implementations ▁are ▁not ▁officially ▁given ▁access ▁to ▁the ▁dec ryption ▁keys ▁or ▁license ▁to ▁the ▁pat ents ▁involved ▁in ▁CSS . ▁Prop ri et ary ▁software ▁players ▁were ▁also ▁difficult ▁to ▁find ▁on ▁some ▁platforms . ▁However , ▁a ▁successful ▁effort ▁has ▁been ▁made ▁to ▁write ▁a ▁dec oder ▁by ▁reverse ▁engineering , ▁resulting ▁in ▁De CSS . ▁This ▁has ▁led ▁to ▁long - running ▁legal ▁batt les ▁and ▁the ▁arrest ▁of ▁some ▁of ▁those ▁involved ▁in ▁creating ▁or ▁distrib uting ▁the ▁De CSS ▁code , ▁through ▁the ▁use ▁of ▁the ▁controvers ial ▁U . S . ▁Digital ▁Mill en ni um ▁Copy right ▁Act ▁( DM CA ), ▁on ▁the ▁grounds ▁that ▁such ▁software ▁could ▁also ▁be ▁used ▁to ▁facil itate ▁una ut hor ized ▁copying ▁of ▁the ▁data ▁on ▁the ▁disc s . ▁The ▁V ide olan ▁team , ▁however , ▁went ▁on ▁to ▁make ▁the ▁lib d vd css ▁library . ▁Un like ▁De CSS , ▁lib d vd css ▁can ▁access ▁a ▁CSS - enc rypted ▁DVD ▁without ▁the ▁need ▁of ▁a ▁crack ed ▁key , ▁thus ▁en abling ▁play back ▁of ▁such ▁disc s ▁on ▁opens ource ▁players ▁without ▁legal ▁rest raint s ▁( although ▁DVD ▁r ipp ers ▁using ▁this ▁library ▁may ▁still ▁be ▁subject ▁to ▁restrictions ). ▁ ▁The ▁DM CA ▁currently ▁affect s ▁only ▁the ▁United ▁States , ▁however ▁many ▁other ▁countries ▁are ▁sign ator ies ▁to ▁the ▁similar ▁W IP O ▁Tre