NEW DELHI: Authorities have detected 18 lakh cases after demonetisation where the income profiles of people do not match their account profile, the Lok Sabha was informed on Friday.Preliminary information has been sought from such people and many have responded. Those who have not given details would be issued with notices as per procedure, finance minister Arun Jaitley said during Question Hour.Responding to supplementaries, he said there was an extended footprint of digitisation in the banking sector. With digitisation, the risk of tampering of technology also increases.But banks are also hiring experts to develop firewalls around their system to make it increasingly difficult to breach it, Jaitley said, adding that technology has to keep pace with crime.He also said that risk assessment was a continuous process for banks who do it individually and collectively.In his written response, Jaitley said as on March 31, 2016, 29 per cent of the savings accounts of public sector banks and regional rural banks sponsored by them were inoperative or lying dormant.A variety of factors have a bearing on an account being inoperative. These may include factors like opening of a new account with change of residence or office, death of the account holder or the relative convenience of operating different accounts, he said.