The body running India's biometrics-based national identity card system has warned people against sharing their unique card number publicly after the country's telecom regulator tweeted his in a challenge to critics to do him "any harm".
India's push to make the Aadhaar card mandatory in everything from opening and maintaining bank accounts to using mobile phone connections has worried privacy advocates.
Critics say the system links enough data to create a comprehensive profile of a person's spending habits, their friends and acquaintances, the property they own, and a trove of other information.
A number of publications have reported several cases of Aadhaar breaches but the Unique Identification Authority of India (UIDAI), the body managing Aadhaar, maintains that the system is safe.
RS Sharma, the head of the Telecom Regulatory Authority of India (TRAI) and the UIDAI's first director general, last week posted his Aadhaar number on Twitter after users challenged him to share the details to prove it was a safe system.
Sharma's tweet started a debate on Twitter, drawing criticism from some quarters while also prompting many to share their Aadhaar numbers.
As Twitter users dug out Sharma's personal details - including his phone numbers, WhatsApp profile, the brand of smartphone that he carries and his address - Sharma insisted he had not been harmed.
The UIDAI issued a statement advising people against sharing their Aadhaar number online.
"Such activities are uncalled for and should be refrained as these are not in accordance with the law," the UIDAI said, adding that the number was sensitive information just like bank account or passport numbers.
People making Aadhaar numbers public or encouraging others to do so could be liable for prosecution and penal action, UIDAI said.
It was not immediately known if the UIDAI would take penal action against Sharma. He was not reachable for comment.
© Thomson Reuters 2018