There is a lot the Unique Identiy (UID) number will do. And a lot that it can't. The UID number will guarantee identity. This alone, by eliminating duplication of beneficiaries in government schemes, could save the government upwards of Rs 20,000 crore a year. That is not all, by allowing access of database to private sector, the UID authority will earn upto Rs 300 crore a year.