@Morgan How about "slave name"?
@starbreaker How about not? Re-assignation the names of those taken into slavery isn't a dead practice, and conflating government aliases with that just diminishes that.
(My mom had her name changed on her when she was taken from her family by US Marshals... in the 60s. _She_ has a slave name. You do not.)
@emsenn Good point.
@starbreaker @Morgan how about 'tracking cookie'?