"Facebook, can pick up any message sent by one person to another if it wants to snoop. Our Aadhar scheme is far more secure."

What harm can Aadhaar do when the Right to Privacy of a citizen has become a futile notion in an era when Facebook can track every detail, thought and movement through its 'WhatsApp' software application, Attorney General (A-G) Mukul Rohatgi asked a Constitution Bench of the Supreme Court on Wednesday.

"There is no absolute privacy. It's a futile notion. Facebook, if it wants, can pick up any message sent by one person to another if it wants to snoop through WhatsApp. Our system (Aadhaar scheme) is far more secure," Mr. Rohatgi, for Unique Identification Authority of India (UIDAI), submitted in court.

"YouTube could pick your choice of films and songs the next time you log in. There are software applications which can pinpoint your location and estimate the time it would reach the destination... Where is privacy here?" Mr. Rohatgi asked.

The maiden hearing of the five-judge Bench led by Chief Justice H.L. Dattu saw the government go to great lengths to convince that Aadhaar is a "voluntary authentication device" and not a snooping device or meant to be an instrument of control of the likes used by authoritarian States to keep tabs on citizens.

"But in many schemes Aadhar is a condition precedent... How does this and your claim that Aadhar enrolment is voluntary go hand- in-hand," Justice Amitava Roy asked from the Bench.

To this, Mr. Rohatgi illustrated the case of a poor widow who has to travel 20 miles every month to her bank to draw her pension.

"If she voluntarily enrols for Aadhaar, there is a scheme that a bank employee comes with the money to her house. If she does not opt for Aadhaar, she continues to go to the bank like how she did before," Mr. Rohatgi said.

He said the Aadhaar was the most widely held identity card in the country at 92 crore compared to seven crore persons holding PAN card, five crore with passports and 12 to 15 crore with ration cards.

He said Rs. 7000 crore has been spent on reaching Aadhaar to the people.

The Constitution Bench was hearing a batch of petitions challenging an August 11 interim order by a three-judge Bench making Aadhaar optional for all government welfare schemes including PDS and LPG cooking gas distribution.

The applications by various bodies, including the RBI, SEBI, TRAI had sought modification of the August order, arguing that the order denied Aadhaar holders easy access to government services.

During the hearing, Chief Justice Dattu said the court is still undecided whether the Aadhar issue should be further referred to a bench of nine or eleven judges.

Aadhaar: voluntary or mandatory?

The Bench asked the government side whether it was willing to give a statement that Aadhar would continue to be voluntary and not mandatory till either the parliament makes a law or the apex court finally decided whether it was an invasion into right to privacy.

Replying positively, A-G said the government has always maintained that Aadhaar scheme was voluntary.

However, senior advocate Shyam Diwan, who appeared for Justice Puttaswamy, the lead petitioner seeking to scrap the Aadhar scheme, argued that there is no point from drawing such empty assurances from the government.

He said citizens are compelled to give away their biometric and personal details despite a 2013 Supreme Court order making Aadhar voluntary.

"There is no gainsay from such statements," Mr. Diwan pointed out.