Who can identify as an Indigenous Australian person?

The Australian Bureau of Statistics defines an Indigenous person as a person of Aboriginal or Torres Strait Islander descent who identifies as an Aboriginal or Torres Strait Islander and is accepted as such by the community in which he or she lives, and more.......
http://www.whatworks.edu.au/dbAction.do?cmd=displaySitePage1&subcmd=select&id=369

The Aboriginal flag    www.aiatsis.gov.au/fastfacts/aboriginalflag.html‎

Aboriginal flag was designed by Harold Thomas, and more.........