Trying to allay the apprehensions expressed on the use of eye scan in preparation of unique number to all residents of the country, UIDAI has come out with a status paper on collecting iris biometrics.

Questions were raised from certain quarters about the need for the iris scan even when the finger prints of all ten fingers and a face scan was also being taken.

It was felt that the iris scan would be an expensive procedure and that there was a risk of a vendor lock-in in the UIDAI project besides other worries.

The Authority headed by Nandan Nilekani said, "A concern with iris has been on cost. However, the current high prices for iris technology are a result of low volume and its use in cost insensitive security applications. Considering the large demand that will come from India for iris devices and software, the UIDAI expects the prices for iris devices and software will fall rapidly."

It said taking into account expert assessments, UIDAI expects iris software to be less expensive by 30-50 per cent compared to fingerprint matching software.

On the risk of vendor lock, the paper said UID Authority had carefully evaluated the available choices among iris technology vendors and concluded that lock-in can be avoided.

It said the Authority will adopt a three-pronged approach to avoid lock-in.

It said the ensure uniqueness, the UIDAI has to minimise the false acceptance rate (FAR) in its biometrics.

"However, the Biometrics Committee (that was set up to suggest the kind of biometrics needed) noted that the approach using fingerprint biometrics alone, in addition to face, faces two challenges in ensuring uniqueness and low FAR within the Indian environment -- the varying quality of fingerprints, particularly among poor residents and the scale of database, at 1.2 billion records. Both these challenges could make uniqueness in biometrics difficult to achieve," it said.

The paper said the risk that fingerprinting may not be sufficient to ensure uniqueness is not a risk that can be ignored, particularly when enrolling residents on such a large scale.

"The cost and logistics of going back and re-enrolling residents, in case the biometrics set is insufficient, would be unacceptable," it said.

"The addition of iris to finger and face biometrics would help the UIDAI achieve accuracy rates that go beyond 95 per cent and would ensure very low FAR. This will also make the UID number highly robust, and enable the number to be used in a wide variety of applications that require high security, such as in financial transactions," the paper said.