Aadhar has large parts of open source technology in it. Even the enrollment and authentication server is opensource.
They have also released an API for getting data from aadhar servers. Complete Technology write up here: http://uidai.gov.in/index.php?option=com_content&view=article&id=153&Itemid=13 -- l...@iitd - http://tinyurl.com/ycueutm
