▁mechan isms ▁can ▁be ▁as ▁simple ▁as ▁file ▁permissions . ▁However , ▁need ▁for ▁more ▁string ent ▁controlled ▁access ▁to ▁data ▁is ▁done ▁using ▁Access ▁Control ▁List s ▁( AC L s ), ▁Ro le - B ased ▁Access ▁Control ▁( R B AC ) ▁and ▁Task ed - B ased ▁Author ization ▁Control s ▁( TB AC ). ▁These ▁types ▁of ▁controls ▁can ▁be ▁used ▁to ▁provide ▁gran ular ▁access ▁to ▁files ▁to ▁include ▁limits ▁on ▁access ▁times , ▁duration ▁of ▁access ▁to ▁gran ular ▁controls ▁that ▁determine ▁which ▁files ▁can ▁be ▁read ▁or ▁written ▁to . ▁The ▁final ▁data ▁access ▁service ▁that ▁might ▁be ▁present ▁to ▁protect ▁the ▁confident ial ity ▁of ▁the ▁data ▁transport ▁is ▁encryption . ▁The ▁most ▁common ▁form ▁of ▁encryption ▁for ▁this ▁task ▁has ▁been ▁the ▁use ▁of ▁SSL ▁while ▁in ▁transport . ▁While ▁all ▁of ▁these ▁access ▁services ▁operate ▁within ▁the ▁data ▁grid , ▁access ▁services ▁within ▁the ▁various ▁administrative ▁domains ▁that ▁host ▁the ▁datasets ▁will ▁still ▁stay ▁in ▁place ▁to ▁en force ▁access ▁rules . ▁The ▁data ▁grid ▁access ▁services ▁must ▁be ▁in ▁step ▁with ▁the ▁administrative ▁domains ▁access ▁services ▁for ▁this ▁to ▁work . ▁ ▁Data ▁rep lication ▁service ▁To ▁meet ▁the ▁needs ▁for ▁scal ability , ▁fast ▁access ▁and ▁user ▁collaboration , ▁most ▁data ▁gr ids ▁support ▁rep lication ▁of ▁datasets ▁to ▁points ▁within ▁the ▁distributed ▁storage ▁architecture . ▁The ▁use ▁of ▁rep lic as ▁allows ▁multiple ▁users ▁faster ▁access ▁to ▁datasets ▁and ▁the ▁pres ervation ▁of ▁band width ▁since ▁rep lic as