The Election Commission of India today informed the Supreme Court that all three units of the EVM – Ballot Unit, Control Unit and VVPAT – have their own microcontroller that cannot be altered once data is burned into it. The ECI informed a bench presided over by Justice Sanjiv Khanna that these microcontrollers are kept in a secure unauthorised access module to avoid physical access. The poll body further said that the microcontrollers used in the EVMs are ‘one-time programmable’ and once this program is burnt into the device at the time of manufacturing, it cannot be altered later.
The bench was also told that two PSUs – Electronics Corporation of India Limited and Bharat Electronics Limited – prepare the symbol loading units (SLUs). The EC also clarified that the data in the EVMs remains preserved till the expiry of the 45-day limitation period after the counting is over.