In a ruling by the 3rd Panel in REsp 2159442/PR (2024/0267355-0), the Superior Court of Justice (STJ) recognized the validity of an electronic signature made through a digital platform not certified by the Brazilian Public Key Infrastructure (ICP-Brasil).
This decision allowed the continuation of a search and seizure procedure based on Provisional Measure 2.200/2001 (MPV), which established ICP-Brasil. This MPV states (art. 10, § 2) that it is possible to use "other means of proving the authorship and integrity of documents in electronic form, including those using certificates not issued by ICP-Brasil, as long as accepted by the parties as valid or acknowledged by the person to whom the document is opposed." Based on this, the 3rd Panel understood that:
The legislators intention was to create different levels of probative force for electronic signatures (in their simple, advanced, or qualified forms) according to the technological method of authentication used by the parties, while simultaneously granting legal validity to any of these modalities, taking into account private autonomy and the freedom of expression of will among individuals. [emphasis added]
The decision introduces a practical application of certain flexibility, as electronic signatures outside the ICP-Brasil system can be valid, provided there is consensus among the involved parties regarding their acceptance. The lower courts that ruled on this case had interpreted it differently, understanding that signatures obtained through private authentication platforms lacked sufficient strength to guarantee authenticity and prevent fraud.
Next, we list the different types of electronic signatures recognized in Brazil to clarify their differences and the applicability of STJs decision.
An electronic signature is a broad category that includes three types of signatures, which differ in the level of reliability regarding the identification of the signatories and their expression of will. The three types listed in the Brazilian legislation are:
- Simple Electronic Signature: it only identifies the signatory and associates data with other data of the signatory in electronic format.
- Advanced Electronic Signature: it uses certificates not issued by the ICP-Brasil system or other means to prove the authorship and integrity of electronic documents. It must be accepted by the parties involved or by the person to whom the signed document is presented.Some of its attributes are:
(i) unequivocal association with the signatory;
(ii) a high level of reliability to exclusively control the data used to create the signature;
(iii) detection of subsequent modification. - Qualified Electronic Signature: This is the "digital signature”, validated through a digital certificate issued by the ICP-Brasil system. The chain of authorities involved issues a digital certificate, ensuring the authenticity, integrity, and legal validity of documents signed digitally.
According to the ruling, the "advanced electronic signature would be equivalent to a recognized signature by resemblance, while the qualified electronic signature would be equivalent to a recognized signature by authenticity." Both are thus valid, differing only in terms of probative force and the "degree of difficulty in technically challenging their aspects of integrity and authenticity."
The ruling, therefore, acknowledges a greater probative force for qualified signatures but does not dismiss the legal validity of advanced signatures, as classified above.
This topic is also relevant for the formation of an enforceable title, as provided in art. 784, § 4 of the Civil Procedure Code (as amended by Law 14,620/2023 ), which expressly admits any type of electronic signature permitted by law, even waiving the requirement for witness signatures when integrity is verified by a signature provider.
The STJ, therefore, takes an important step by reaffirming the value of tools available in the new reality of the virtual world, rejecting excessive formalism.
The TMT and Digital Law team at Azevedo Sette Advogados remains available for any clarifications and contributions on the subject.