Public security test of electronic voting machines in Brazil completes 30 years with no flaws found

One example is the so-called Security Test, an initiative that allows computer experts and any Brazilian citizen over 18 years of age to try to find vulnerabilities in the systems used in electronic voting machines.

One of the main targets of the tests is the source code of the ballot box's systems. It is the set of instructions that determines how the software should work. According to the TSE, since the first edition of the test, in 2009, no participant has managed to find a flaw capable of compromising the secrecy of the vote or the result of an election.

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The public security test is just one of the verification mechanisms used by the Electoral Court. Check out the main steps of the process:

A year before the election, the source codes of electoral systems are opened for analysis. Authorized entities can examine the codes, monitor the functioning of the systems and request clarifications from the TSE.

Closer to voting, the ballot boxes that will be used undergo a digital signature and sealing process. From that moment on, any changes to the programs can be identified.

On election day, some ballot boxes are drawn to pass the integrity test. The day before, representatives of entities and parties fill out paper ballots with votes and deposit them in a canvas ballot box. On voting day, the same votes are typed into the electronic ballot box drawn for the test — the entire process is monitored and filmed.

At the end, a comparison is made between the result recorded by the electronic voting machine and the votes filled in on paper ballots. This is how, in practice, it is verified whether the equipment correctly records and counts the votes.

Before voting begins, each ballot box issues the so-called "zerésima", a document that proves that the equipment started the day without any votes registered.

At the end of voting, the ballot box issues the ballot box, with the total votes received by each candidate and party, in addition to blank and invalid votes. A copy of the ballot is posted at the voting station, and the document contains a QR Code that can be read by anyone, allowing the results of that ballot box to be compared with the data published later by the TSE.

The electronic voting system is not new: the electronic ballot box turned 30 years old in 2026. Since its debut, 15 computerized elections have been held in Brazil — the one in October will be the sixteenth.