STATISTICAL HAIR ON BLACK-HOLES

The Bekenstein-Hawking entropy for certain BPS-saturated black holes i n string theory has recently been derived by counting internal black h ole microstates at weak coupling. We argue that the black hole microst ate can be measured by interference experiments even in the strong cou pling region where there is clearly an event horizon. Extracting infor mation which is naively behind the event horizon is possible due to th e existence of statistical quantum hair carried by the black hole. Thi s quantum hair arises from the arbitrarily large number of discrete ga uge symmetries present in string theory.