Contrary to claims by Indian election authorities, these paperless electronic voting systems suffer from significant vulnerabilities. Even brief access to the machines could allow dishonest election insiders or other criminals to alter election results.

https://youtu.be/ZlCOj1dElDY

In the video above, we demonstrate two kinds of attacks against a real Indian EVM. One attack involves replacing a small part of the machine with a look-alike component that can be silently instructed to steal a percentage of the votes in favour of a chosen candidate. These instructions can be sent wirelessly from a mobile phone. Another attack uses a pocket-sized device to change the votes stored in the EVM between the election and the public counting session, which in India can be weeks later.

These attacks are neither complicated nor difficult to perform, but they would be hard to detect or defend against. The best way to prevent them is to count votes using paper ballots that voters can see.

Also Read Problem with EVMs

http://www.thehindu.com/opinion/op-ed/The-problem-with-EVMs/article13369610.ece