Electronic signatures in Brazil

The laws: MP 2.200-2 and Lei 14.063

Medida Provisória nº 2.200-2, of August 24, 2001, created ICP-Brasil, the Brazilian public key infrastructure. It remains in force with the status of law under article 2 of Constitutional Amendment 32/2001. Its article 10 is the rule for electronic documents:

• Electronic documents are public or private documents "para todos os fins legais" (for all legal purposes).
• §1: declarations in electronic documents produced with ICP-Brasil certification "presumem-se verdadeiros em relação aos signatários" (are presumed true in relation to the signers).
• §2: the MP doesn't prevent "outro meio de comprovação da autoria e integridade de documentos em forma eletrônica, inclusive os que utilizem certificados não emitidos pela ICP-Brasil, desde que admitido pelas partes como válido ou aceito pela pessoa a quem for oposto o documento" (other means of proving the authorship and integrity of electronic documents, including certificates not issued by ICP-Brasil, provided the parties admit it as valid or the person the document is used against accepts it).

Lei 14.063, of September 23, 2020, classifies electronic signatures in three tiers (article 4). Its rules on use apply to dealings with and within public bodies, not to interactions between private persons (article 2, sole paragraph, II(a)); between private parties, MP 2.200-2's article 10 is the operative rule, and courts use Lei 14.063's vocabulary.

The Código Civil adds freedom of form: "A validade da declaração de vontade não dependerá de forma especial, senão quando a lei expressamente a exigir" (article 107).

Simple, advanced and qualified

Tier (Lei 14.063, article 4)	What it requires	Effect
Simples (simple)	One "que permite identificar o seu signatário", or that "anexa ou associa dados a outros dados em formato eletrônico do signatário" (I)	Valid, with no statutory presumption. Before public bodies, admitted in lower-impact interactions with no confidential information (article 5, §1, I)
Avançada (advanced)	Certificates not issued by ICP-Brasil or other means of proving authorship and integrity, admitted by the parties as valid or accepted by the person the document is used against, and: uniquely associated with the signer; created with data the signer can, with a high level of confidence, operate under their exclusive control; linked to the signed data so any later change is detectable (II)	Admitted for more public-sector uses, such as registering acts at the commercial registries (article 5, §1, II), and an advanced or qualified signature is required to send information to public registries over the internet (Lei 6.015, article 17, §1)
Qualificada (qualified)	A digital certificate under MP 2.200-2 article 10, §1, that is, an ICP-Brasil certificate (III)	Presumed true in relation to the signers (MP 2.200-2 article 10, §1), with the "nível mais elevado de confiabilidade" (highest level of reliability, article 4, §1). Mandatory in the cases of article 5, §2, such as most electronic invoices and "atos de transferência e de registro de bens imóveis"

What the courts say

In REsp 2.159.442, reported by the Superior Tribunal de Justiça on December 3, 2024, the STJ's Third Panel held unanimously that the presumption of truth of an electronic signature certified by a private company can't be set aside merely because that company isn't accredited in ICP-Brasil. The rapporteur, Justice Nancy Andrighi, relied on MP 2.200-2 article 10, §2, noted that the parties had expressly agreed to sign through a platform chosen by the creditor, and said refusing such signatures would be "excessivo formalismo" (excessive formalism).

Proving an electronic signature

• Any lawful evidence. Parties may use all lawful and morally legitimate means of proof (Código de Processo Civil, article 369), and the judge assesses the value of an electronic document (article 440).
• Authenticity. A document is authentic when a notary recognizes the signature, when "a autoria estiver identificada por qualquer outro meio legal de certificação, inclusive eletrônico, nos termos da lei", or when the party it is produced against doesn't challenge it (article 411).
• Burden. If authenticity is challenged, the document loses credibility until proven (article 428, I), and the burden of proof falls on the party that produced it (article 429, II). Only an ICP-Brasil signature carries the statutory presumption.

Documents with their own rules

• Real estate. A public deed (escritura pública) is essential for acts on real rights in real estate worth more than thirty times the highest minimum wage, unless the law says otherwise (Código Civil article 108). Transfer and registration of real estate before public bodies requires a qualified signature (Lei 14.063 article 5, §2, IV).
• Notarial acts. An electronic notarial act requires a notarial videoconference, the parties' signatures "exclusivamente por meio do e-Notariado" and the notary's ICP-Brasil signature, and remote notarial acts collecting signatures without e-Notariado are prohibited (Provimento CNJ 149/2023, articles 286 and 318).
• Prenuptial agreements are void unless made by public deed (Código Civil article 1.653).
• Wills. A public will is written by a notary and read aloud before two witnesses (article 1.864), and a private will is read and signed before at least three witnesses (article 1.876).
• Health documents. Controlled-substance prescriptions and medical certificates require a qualified signature, and other documents signed by health professionals at least an advanced one (Lei 14.063 articles 13 and 14).

Witnesses and enforcement titles

A private document signed by the debtor and two witnesses is an out-of-court enforcement title, a título executivo extrajudicial (CPC article 784, III). For titles created or attested electronically, "é admitida qualquer modalidade de assinatura eletrônica prevista em lei, dispensada a assinatura de testemunhas quando sua integridade for conferida por provedor de assinatura" (any legal type of electronic signature is accepted, and witnesses may be dispensed with when a signature provider confirms integrity; article 784, §4). This affects enforceability, not validity.

How to make an electronic signature hold up

1. Add an acceptance clause. State in the contract that the parties accept the signing method as valid, which is the condition of MP 2.200-2 article 10, §2, and the agreement the STJ relied on.
2. Keep evidence of authorship and integrity, since a challenged document must be proven by the party that produced it (CPC article 429, II); see how to prove someone signed electronically.
3. Use a notary or ICP-Brasil where the law requires a public deed, e-Notariado or a qualified signature.

How Attest fits ordinary business agreements

Attest signatures are electronic signatures in the simple tier of Lei 14.063 (article 4, I) and, between private parties, an "outro meio de comprovação da autoria e integridade" under MP 2.200-2 article 10, §2, effective when the parties admit it as valid. They are not qualified signatures, because Attest issues no ICP-Brasil certificates, and Attest doesn't claim the advanced tier. For everyday agreements such as service contracts, statements of work, NDAs and supplier agreements, each signature carries the evidence article 10, §2 talks about:

What the law asks you to prove	What Attest records
Authorship (MP 2.200-2 article 10, §2)	Each signature is made with a passkey registered to the signer's email address. A passkey is a cryptographic key only the signer controls, unlocked with Face ID, Touch ID, Windows Hello or the device PIN, and it must confirm the signer is present and verified. Attest checks each signature against the passkey's public key. Attest confirms control of the email address and the passkey, not a government ID
Integrity (article 10, §2)	The passkey signs a statement that begins "I have reviewed and I sign", with the SHA-256 fingerprint of the exact document and of the signer's entries, and the signed state is anchored on the Horizen public blockchain. Change one byte and verification fails
Acceptance (article 10, §2)	The acceptance clause you put in the contract: each signer's passkey signature covers it, because the signed statement names the exact document by its fingerprint
Authenticity if challenged (CPC article 429, II)	Every party downloads the same sealed PDF: the signed pages, with a "Signed with Attest" stamp on each signature and a seal line at the foot of every page, a certificate of completion, the audit trail up to completion and a "Verify it yourself, without us" page, with the full evidence, the original document and a standalone verifier attached inside

A fingerprint (SHA-256 hash) is a short code calculated from a file's contents that changes if a single byte changes. The open-source verifier inside the copy runs in any browser without any Attest service and checks each signer's passkey signature, the original document, the pages you see and Attest's anchored record on Horizen.

For a public deed, an e-Notariado act, a registry filing, or any act that requires a qualified ICP-Brasil signature, use a notary or an ICP-Brasil certificate.

Every document is end-to-end encrypted, so Attest can't read it. Signers need no account and never pay, and anyone can verify a signed copy for free at attest.datahubz.com/verify. Your first 2 documents are free, in total, then the Signing plan is $5 a month for 20 documents.