Prelims level : Indian polity and Governance Mains level : Important aspects of governance, transparency and accountability
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Why in News:

  • Supreme Court’s solution of increased VVPAT verification should reassure the EVM doubt accepted questions.


  • The increase in the overall number of EVMs to be counted to close to 20,000 machines, should reasonably address the very remote possibility of ‘insider fraud’.
  • It will also verify a higher sample of EVMs in the smaller States and bring the sample within reasonable confidence levels to discount chances of EVM-tampering
  • Higher EVM’s would effectively blunt criticism that may reduce the doubt in electoral process The ECI made technical fixes to the VVPAT to make them more resilient during use across the country, and it should be well-prepared to handle any malfunction during the seven- phase Lok Sabha election.
  • It is time for the ECI to focus on the hassle-free conduct of polls to the Lok Sabha.


  • The Voter Verified Paper Audit Trail is a method that provides feedback to voters.
  • It is an independent verification printer machine and is attached to electronic voting machines.
  • It allows voters to verify if their vote has gone to the intended candidate.
  • When a voter presses a button in the EVM, a paper slip is printed through the VVPAT. The slip contains the poll symbol and name of the candidate. It allows the voter to verify his/her choice. After being visible to the voter from a glass case in the VVPAT for seven seconds, the ballot slip will be cut and dropped into the drop box in the VVPAT machine and a beep will be heard. VVPAT machines can be accessed by polling officers only.

how does it work?

  • EVMs are electronic voting machines which provide the voter with a button for for each choice and it is connected by a cable to an electronic ballot box.
  • It consists of two units – control unit and balloting unit– which are connected by a 5-metre cable.
  • The control unit is with the Election Commission appointed polling officer and the Balloting Unit is in the voting compartment into which the voter enters to cast his/her vote in secret by pressing the button against the name and symbol of the candidate of his/her choice.
  • The EVM runs on a 6-volt single alkaline battery fitted in the control unit, and can even be used in areas that have no electricity.

Why tampering of EVMs is impossible or very difficult?

  • The machine is electronically protected to prevent any tampering/manipulation. The programme (software) used in these machines is burnt into a One Time Programmable (OTP)/Masked chip so that it cannot be altered or tampered with. Further these machines are not networked either by wire or by wireless to any other machine or system. Therefore, there is no possibility of its data corruption.
  • The software of EVMs is developed in-house by a selected group of Engineers in BEL (Defense Ministry PSU) and ECIL (Atomic Energy Ministry’s PSU) independently from each other. A select software development group of 2-3 engineers designs the source code and this work is not sub-contracted.
  • After completion of software design, testing and evaluation of the software is carried out by an independent testing group as per the software requirements specifications (SRS). This ensures that the software has really been written as per the requirements laid down for its intended use only.
  • After successful completion of such evaluation, machine code of the source programme code is given to the micro controller manufacturer for writing in the micro controllers. From this machine code, the source code cannot be read. Source code is never handed over to anyone outside the software group of PSUs.
  • Micro controller manufacturer initially provides engineering samples to PSUs for evaluation. These samples are assembled into the EVM, evaluated and verified for functionality at great length. Bulk production clearance by PSU is given to micro controller manufacturer only after successful completion of this verification.
  • The source code for the EVM is stored under controlled conditions at all times. Checks and balances are in place to ensure that it is accessible to authorized personnel only.
  • During production in the factory, functional testing is done by production group as per the laid down Quality plan and performance test procedures.
  • The software is so designed that it allows a voter to cast the vote only once. The vote can be recorded by an elector from the ballot unit only after the Presiding Officer enables the ballot on the Control Unit.
  • The machine does not receive any signal from outside at any time. The next vote can be recorded only after the Presiding Officer enables the ballot on the Control Unit. In between, the machine becomes dead to any signal from outside (except from the Control Unit).
  • Samples of EVMs from production batches are regularly checked for functionality by Quality Assurance Group, which is an independent unit within the PSUs.
  • Certain additional features were introduced in 2006 in ECI-EVMs such as dynamic coding between Ballot Unit (BU) and Control Unit (CU), installation of real time clock, installation of full display system and date and time stamping of every key-pressing in EVM.
  • Technical Evaluation Committee in 2006 has concluded that any tempering of CU by coded signals by wireless or outside or Bluetooth or WiFi is ruled out as CU does not have high frequency receiver and data decoder. CU accepts only specially encrypted and dynamically coded data from BU. Data from any outside source cannot be accepted by CU.

Advantages of EVMs include:

  • Cost effective.
  • Eliminates need for production and printing of ballot papers
  • A substantial reduction in expenses happens when it comes to transportation, storage, and recruiting counting staff.
  • Environment friendly- No use of papers; ‘Greener’ and can be used repeatedly
  • Time effective- Reduction in time taken in election procedures Results can be stored in machine memory; later deleted manually Reduction in invalid votes
  • Prevent booth capturing
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