While the two sides have not yet finalized the details, Alexandre de Moraes, Brazil’s elections chief, said he would try to have some tests carried out on Election Day on machines that had just been used by voters, as the military has requested, according to a person involved in the meeting who spoke on the condition of anonymity because the talks were private.
Fábio Faria, Brazil’s communications minister and a senior adviser to Mr. Bolsonaro, said in a text message that Mr. Faria felt the issue had been resolved.
With less than five weeks left before the election, the agreement represented a notable détente that could weaken the president’s ability to claim voter fraud.
Brazil’s armed forces have been a key ally of Mr. Bolsonaro in his criticism of the voting machines as vulnerable to fraud, despite little evidence. Mr. Bolsonaro, in turn, has said that he trusts the armed forces to ensure the elections are safe. In recent interviews, military officials have said that the security tests were their principal remaining concern. And now it appears that election officials are trying to comply with the military’s requests.
The easing of tensions is positive for the outlook of Brazil’s elections, but Mr. Bolsonaro has agreed to similar truces in the past and then later continued his criticism of the electoral system.
Brazil’s election officials have been planning to run security tests on 600 voting machines on Election Day by simulating the voting process on each machine. Those tests are scheduled to be completed in a controlled room outside voting stations.
The military has said it is concerned that sophisticated malicious software could evade such simulated tests. For example, hacking software could be designed not to activate unless a real voter unlocked the machine with a fingerprint.
Election security experts in Brazil have said such a scenario is technically possible but highly unlikely because of other controls in the voting machines. There has been no evidence of material fraud in Brazil’s voting machines.
To solve for the hypothetical, the military has asked for security tests to be completed in actual voting centers during the election, on machines that were just used by actual voters.
Elections officials had previously said such changes to the security tests so close to Election Day were not feasible. But on Wednesday, Mr. Moraes told Paulo Sérgio Nogueira, Brazil’s defense minister, that he would try to change the security tests for a limited number of machines. Military officials have suggested changing the tests for two to four machines per state in Brazil, but Mr. Moraes said Wednesday that he needed to discuss the issue with other elections officials to determine how many would be possible, according to the person involved in the meeting.
The meeting over coffee between Mr. Moraes and Mr. Nogueira was positive and cordial, the person said.
Military officials have said that they want certainty that there is no malicious software installed on the machines because Brazil’s voting system lacks paper backups for potential audits if there is suspicion of fraud.
Mr. Bolsonaro has repeatedly claimed that the voting machines can be hacked, but when pressed for evidence, he has cited a 2018 hack of election officials’ computer network, which is not connected to the voting machines. A federal investigation into that hack concluded that the hackers could not gain access to any voting machines. Mr. Bolsonaro has not presented other evidence of past fraud.