One of the traditional ways to vote is outside the polling district of the voter’s residence. This means that during the voting, the voter puts his or her vote into double envelope and the envelope is delivered to the voter’s polling division of residence. The general concept of I-voting has been derived from the above-mentioned voting outside the polling district of residence. What is similar in these two voting methods is the way of checking that the vote has been cast only once and guaranteeing the anonymity of vote.

In order to understand the I-voting system better, the envelope voting method used in Estonia should be described shortly:

• A voter presents an ID document to be identified.
• The voter then receives the ballot and two envelopes.
• The voter fills in ballot paper and puts it into the envelope, which has no information about the voter.
• Then he encloses the envelope into outer envelope on which the voter's information is written.
• The envelope is delivered to the voter’s polling division of residence. After the eligibility of the voter is determined, the outer envelope is opened and the inner (anonymous) envelope is put into the ballot box.

The system guarantees that the voter’s choice shall remain secret and recording the vote in the list of voters in the polling district of residence prevents voting more than once.

I-voting is carried out according to the same scheme. The downloaded I-voting application encrypts the vote. The encrypted vote can be regarded as a vote contained in the inner, anonymous envelope. After that the voter gives a digital signature to confirm his or her choice. By digital signing, the voter’s personal data or outer envelope are added to the encrypted vote. 

Verification of electronic votes (I-votes) enables to receive more accurate information on the security of the computer that was used to cast the I-vote. Verification makes it possible to detect when the computer is infected with malware that changes the I-vote or blocks the I-voting.According to the Riigikogu Election Act the verification of I-votes shall not be implemented before 2015. The system was tested first at 2013 local elections. Voters will be able to verify their I-votes with a smart device (mobile phone or a tablet) equipped with a camera and Internet connection. During the 2013 test only Android devices were supported. Support for other platforms (Windows Phone and iOS) was added in 2014. 

Before the ascertaining of voting results in the evening of the Election Day, the encrypted votes and the digital signatures (ie data identifying the voter) are separated. Then anonymous I-votes are opened and counted. The system opens the votes only if they are not connected to personal data. 

For more detailed information read: 
Estonian I-Voting System: General Description.