Electronic Signatures: The Legal Validity of Each Type

This page is a translation of the original Portuguese text, provided for convenience. It deals with Brazilian law. If there is any discrepancy, the Portuguese version prevails. Read the original in Portuguese

Electronic documents now play a central role in legal and commercial dealings. Lawyers, businesses, and ordinary citizens need to understand precisely the three types of electronic signature recognized under Brazilian law. Each offers a different level of security, traceability, and evidentiary weight. Choosing the wrong one can irreversibly compromise contracts, powers of attorney, and administrative acts.

The Legal Framework for Electronic Signatures

The legal framework rests on two pillars: Provisional Measure 2.200-2, of 2001, which created the Brazilian Public Key Infrastructure (ICP-Brasil), and Law 14.063, of 2020, which governs the use of electronic signatures in dealings with public bodies. Even before these laws, Article 107 of the Civil Code already supported the validity of declarations of intent made by electronic means, under the principle of freedom of form.

Law 14.063/2020 established the three-tier classification of electronic signatures. It sets objective criteria for security and for where each type may be used, depending on how reliably the signer is identified and how well the integrity of the document is protected. Decree 10.278/2020 completed this regime by regulating the digitization of paper documents and setting technical standards of authenticity for the entire life cycle of electronic files.

Brazilian law adopted the general principle of functional equivalence from the guidelines of the United Nations Commission on International Trade Law (UNCITRAL). Under this principle, an electronic document has the same legal effect as a paper one when it meets the authenticity and integrity requirements set by law. This gives the whole regime its systematic coherence.

The Three Types and Their Technical Requirements

The simple electronic signature is the most accessible form. It identifies the signer without robust verification mechanisms. Examples include clicking “accept” on a digital form, entering a name and CPF (Brazil’s individual taxpayer number) on a service platform, and sending documents by e-mail with a read confirmation. It is valid for less complex acts, but its evidentiary weight depends on the parties’ ability to show, through other means the law allows, that the declaration of intent was genuine.

The qualified signature, backed by an ICP-Brasil certificate, is the only one that the law expressly gives the same legal effect as a handwritten signature, with no need for additional proof of authenticity.

The advanced electronic signature sits in the middle. The process must be uniquely linked to the signer, must be able to identify the signer accurately, and must have been created using data under the signer’s control. Platforms that use biometric validation, a token sent to a registered mobile phone, or facial recognition fall into this category. The law allows advanced signatures in private contracts of any kind, except for acts that the law requires to take a specific form.

At the top of the hierarchy is the qualified electronic signature, backed by a digital certificate issued by an authority accredited by ICP-Brasil. Under Article 10, paragraph 1, of Provisional Measure 2.200-2/2001, this type is equivalent, for all legal purposes, to a handwritten signature. The most commonly used certificates are type A1 (generated in software) and type A3 (stored on a physical cryptographic device). The A3 is considered the most secure standard because the private key cannot be extracted.

Practical Uses and Legal Limits

The type of signature you choose must match the nature of the legal act, or the transaction may not be valid. A real estate purchase and sale agreement, for example, requires a public deed executed before a notary public’s office. No electronic signature on its own, even a qualified one, can replace the form the law prescribes. Powers of attorney granting broad authority to sell real estate are subject to the same restriction under Article 657 of the Civil Code.

In employment law, Article 74, paragraph 2, of Brazil’s Consolidation of Labor Laws now allows electronic time recording. Contracts entered into electronically are recognized as valid as long as they meet the requirements of Article 444 of the same law. An electronic employment contract may be signed with an advanced or qualified signature, depending on how sensitive the agreed terms are and how much security the nature of the relationship calls for.

The federal public administration requires the qualified type for acts that affect third parties or a citizen’s individual rights, such as issuing certificates and performing binding administrative acts. For internal communications and requests with no immediate external effect, the advanced type is enough, according to the application levels set by the decree that regulates Law 14.063/2020.

Frequently Asked Questions

Is a contract signed with a simple electronic signature legally valid?

Yes, as long as the parties can show the signer’s identity and the document’s integrity by other means of proof the law allows. Article 107 of the Civil Code establishes freedom of form for legal transactions that do not require a special form. A simple signature is therefore enough for ordinary service contracts, leases of movable property, and other acts for which the law does not impose a specific form. The main weakness of this type is its fragile evidentiary weight in a dispute. For that reason, we strongly recommend using platforms that record access logs, IP addresses, and authentication metadata.

What is the practical difference between an A1 certificate and an A3 certificate?

Both are digital certificates issued under ICP-Brasil, and both produce qualified electronic signatures with the same legal value. The difference is technical. An A1 certificate is generated and stored in software, either on the holder’s own computer or in the cloud, and is valid for one year. With an A3 certificate, the private key is stored on an encrypted physical device (a USB token or smart card), which prevents it from being extracted and reduces the risk of misuse. It is valid for one to three years. For acts of greater financial significance or subject to stricter regulatory requirements, the A3 offers a higher level of security and traceability.

Can different signers of the same document use different types of signature?

Yes. Nothing in Brazilian law prevents the parties to one document from signing with different types. Each signer may use whichever type suits their situation and the requirements of the act. In a complex corporate document, partners who hold an ICP-Brasil certificate can sign with the qualified type, while witnesses without a certificate use an advanced signature platform. The document remains fully valid. Each signature is assessed individually according to the type its signer used, and the weakness of one does not taint the others.

As informações deste artigo são de caráter informativo e não substituem consulta jurídica individualizada. Cada caso possui particularidades que exigem análise específica.