▁to ▁only ▁extract ▁the ▁information ▁which ▁is ▁useful ▁to ▁law ▁enfor cement ▁and ▁intelligence ▁ag encies . ▁ ▁Comput ers ▁can ▁be ▁a ▁surve ill ance ▁target ▁because ▁of ▁the ▁personal ▁data ▁stored ▁on ▁them . ▁If ▁someone ▁is ▁able ▁to ▁install ▁software , ▁such ▁as ▁the ▁F BI ' s ▁Magic ▁Lan tern ▁and ▁C IP AV , ▁on ▁a ▁computer ▁system , ▁they ▁can ▁easily ▁gain ▁una ut hor ized ▁access ▁to ▁this ▁data . ▁Such ▁software ▁could ▁be ▁installed ▁phys ically ▁or ▁rem ot ely . ▁Another ▁form ▁of ▁computer ▁surve ill ance , ▁known ▁as ▁van ▁E ck ▁ph re aking , ▁involves ▁reading ▁elect romagnet ic ▁em an ations ▁from ▁computing ▁devices ▁in ▁order ▁to ▁extract ▁data ▁from ▁them ▁at ▁distances ▁of ▁hundreds ▁of ▁meters . ▁The ▁NS A ▁runs ▁a ▁database ▁known ▁as ▁" P in w ale ", ▁which ▁stores ▁and ▁indexes ▁large ▁numbers ▁of ▁emails ▁of ▁both ▁American ▁citizens ▁and ▁foreign ers . ▁Additionally , ▁the ▁NS A ▁runs ▁a ▁program ▁known ▁as ▁PR IS M , ▁which ▁is ▁a ▁data ▁min ing ▁system ▁that ▁gives ▁the ▁United ▁States ▁government ▁direct ▁access ▁to ▁information ▁from ▁technology ▁companies . ▁Through ▁accessing ▁this ▁information , ▁the ▁government ▁is ▁able ▁to ▁obtain ▁search ▁history , ▁emails , ▁stored ▁information , ▁live ▁ch ats , ▁file ▁trans fers , ▁and ▁more . ▁This ▁program ▁generated ▁huge ▁controvers ies ▁in ▁regards ▁to ▁surve ill ance ▁and ▁priv acy , ▁especially ▁from ▁U . S . ▁citizens . ▁ ▁Tele ph