. ▁It ▁could ▁involve ▁user - to - user ▁and ▁user - to - application ▁as ▁well ▁as ▁application - to - application ▁use - case ▁scenarios ▁at ▁both ▁the ▁browser ▁tier ▁as ▁well ▁as ▁the ▁web ▁services ▁or ▁service - orient ed ▁architecture ▁( SO A ) ▁tier . ▁It ▁can ▁involve ▁high - tr ust , ▁high - security ▁scenarios ▁as ▁well ▁as ▁low - tr ust , ▁low - security ▁scenarios . ▁The ▁levels ▁of ▁identity ▁ass urance ▁that ▁may ▁be ▁required ▁for ▁a ▁given ▁scenario ▁are ▁also ▁being ▁standard ized ▁through ▁a ▁common ▁and ▁open ▁Identity ▁Ass urance ▁Framework . ▁It ▁can ▁involve ▁user - cent ric ▁use - cases , ▁as ▁well ▁as ▁enter prise - cent ric ▁use - cases . ▁The ▁term ▁" identity ▁feder ation " ▁is ▁by ▁design ▁a ▁generic ▁term , ▁and ▁is ▁not ▁bound ▁to ▁any ▁one ▁specific ▁protocol , ▁technology , ▁implementation ▁or ▁company . ▁ ▁Identity ▁feder ations ▁may ▁be ▁bi - l ater al ▁relationships ▁or ▁mult il ater al ▁relationships . ▁ ▁In ▁the ▁latter ▁case ▁the ▁mult il ater al ▁feder ation ▁frequently ▁occurs ▁in ▁a ▁vertical ▁market , ▁such ▁as ▁in ▁law ▁enfor cement ▁( such ▁as ▁the ▁National ▁Identity ▁Exchange ▁Federation ▁- ▁N IE F ) ▁and ▁research ▁and ▁education ▁( such ▁as ▁In Common ). ▁If ▁the ▁identity ▁feder ation ▁is ▁bil ater al , ▁the ▁two ▁parties ▁can ▁exchange ▁the ▁necessary ▁metadata ▁( assert ion ▁signing ▁keys , ▁etc .) ▁to ▁implement ▁the