Electronic voting machines used in Indian elections are custom built for the purpose, and cost about $100.
https://en.wikipedia.org/wiki/Indian_voting_machines
All it has is N buttons, accumulators to store presses of each button in non-volatile memory, and a seven-segment LED display to indicate status (ready-to-vote, vote cast, etc.). Vote counting is done offline by connecting to a controller. No wifi or any other remote-access capability.
All that really needs to be done to create a paper trail is to add a printer.
Not implying that they're completely secure, but any breach at least needs physical access to the box. And physical security of the machines is on the same level as those provided for traditional ballot boxes.
Edit 1: The balloting unit does not even have a 7-segment display - just individual LEDs next to their buttons to provide feedback that the button has been pressed.
Edit 2: More details on the internals of the EVM: https://jhalderm.com/pub/papers/evm-ccs10.pdf
https://en.wikipedia.org/wiki/Indian_voting_machines
All it has is N buttons, accumulators to store presses of each button in non-volatile memory, and a seven-segment LED display to indicate status (ready-to-vote, vote cast, etc.). Vote counting is done offline by connecting to a controller. No wifi or any other remote-access capability.
All that really needs to be done to create a paper trail is to add a printer.
Not implying that they're completely secure, but any breach at least needs physical access to the box. And physical security of the machines is on the same level as those provided for traditional ballot boxes.
Edit 1: The balloting unit does not even have a 7-segment display - just individual LEDs next to their buttons to provide feedback that the button has been pressed.
Edit 2: More details on the internals of the EVM: https://jhalderm.com/pub/papers/evm-ccs10.pdf