Brazil's Electoral Court seals voting software with digital signature

Between August and September 2026 the Tribunal Superior Eleitoral (TSE) held a public ceremony to digitally sign and seal the software that runs Brazil's electronic voting machines. According to TSE’s Information Technology secretary Júlio Valente, the signature makes the programs immutable – even the court cannot modify them after the ceremony. Any future change would require a new public signing event with all supervising bodies present.

The sealed software is verified at several stages: during media generation and ballot‑box preparation, political parties and oversight entities can confirm the code matches the sealed version; judges inspect the authenticity of the software in each polling station before voting begins; and similar checks are applied to the transmission systems that send vote tallies to the TSE. Since 2002 the TSE also conducts an Integrity Test, randomly selecting urnas eletrônicas for simulated voting under external audit. Over more than two decades the test has never shown a discrepancy between simulated votes and the machines’ reported results, reinforcing confidence in the electoral process.

Valente emphasized, “Nesse momento, os sistemas estão encerrados, são finalizados, nada mais pode mudar.” The ceremony therefore aims to guarantee that the software used on election day is exactly the one audited and approved months earlier.