UID or aadhaar will have four hidden numbers as per a report published in Business Standard dated April 28. These four numbers will be post fixed to the 12 digit number.

In an exclusive interview to Governance Now earlier, UIDAI Chairman, Nandan Nilekani had said that, "It’s a 12-digit number. There is the name. There is the date of birth. There is the sex. There is the address, father’s name and mother’s name. It’s just four to five fields."

The report in Business Standard quoting Ram Sewak Sharma, Director General of UIDAI mentions, "As far as people are concerned, there would only be a 12-digit number that would be relevant for their identification and use. However, we are making a provision of extra four digits that would be a post-fix for this 12-digit number for pin-based identification. So, UID will become a 16-digit number for our use and the database that we will maintain,”

The report mentions that these additional four digits will change whenever a resident changes his address.

In essence these four digits will be indication of address of a resident and will be of relevance to the Authority. The resident will be using the 12-digit number allotted to him.