Finance Minister Arun Jaitley and his predecessor, P Chidambaram of the Congress, sparred in parliament today over Aadhaar, the biometric identification system that the opposition alleges is not fool-proof in protection of data privacy. Mr Chidambaram held up the example of cricket icon MS Dhoni's wife Sakshi alleging a leak of his Aadhaar details as he asked Mr Jaitley in the Rajya Sabha how the government planned to protect the privacy of transactions, facts and materials.