Document Authentication & Signature Verification Guide

Note: This content describes Brazilian notarial law and procedures.

Document Authentication and Signature Verification: Modalities and Procedure

Document Authentication and Signature Verification: Modalities and Procedure

This article answers

• What is the difference between document authentication and signature verification?
• What are the modalities of signature verification at the notary office (tabelionato de notas)?
• How does opening and maintaining a signature card work at the notary office?
• What are the requirements for authenticating document copies?
• When is in-person signature verification (por autenticidade) mandatory?

In summary

• Document authentication and signature verification are notarial acts provided for by federal legislation to grant public faith, veracity, and effectiveness to copies of original papers and to signatures affixed to private documents.
• This is a federal rule, regulated nationally by notarial legislation and consolidated guidelines of the Judiciary, with secondary variations in each state's Code of Norms (Código de Normas).
• Signature verification is divided into two main modalities: by similarity (por semelhança), through comparing the graphic stroke with the archived signature card, and by authenticity (por autenticidade), which requires physical appearance and signing before the notary clerk.
• Document authentication strictly requires the presentation of the original document in perfect physical condition, allowing the notary office to attest that the checked copy faithfully reproduces the original matrix.

What is the difference between document authentication and signature verification?

Document authentication and signature verification are two distinct notarial instruments, although frequently used together in private legal transactions. The purpose of the notary office (tabelionato de notas) when performing these acts is to grant legal certainty, publicity, and a rebuttable presumption of veracity to documents circulating in society (Lei nº 8.935/1994 [Law No. 8,935/1994], art. 1º) Lei nº 8.935/1994, art. 1º.

In document authentication (autenticação de documentos), the focus of the notarial act falls upon the paper or the documentary medium itself. The notary public (tabelião de notas) or authorized clerk analyzes the original document presented by the interested party and compares it point by point with its reprographic copy (photocopy). Upon verifying that the copy is an exact, faithful, and complete reproduction of the original, free of erasures, alterations, or additions, the notary agent affixes the authentication seal, the inspection stamp, and the signature. The act formally declares that the photocopied document corresponds precisely to its original.

In signature verification (reconhecimento de firma), on the other hand, the focus of the notarial act falls upon the authorship of the signature affixed to a private document. The notary office does not certify the entire content of the contract or written declaration, but rather attests to the graphic authorship of whoever signed that paper. The act of signature verification confirms to society that the handwriting belongs to a specific person, preventing forgery, identity fraud, and repudiation of authorship.

Understanding the distinction between document authentication and signature verification is essential for requesting the correct service at the notary counter. If you need to prove that a copy reproduces a true document, the appropriate act is authentication. If you need to demonstrate that the signature on a contractual statement effectively belongs to the signatory, the necessary procedure is signature verification.

The notary service acts as a guarantor of the authenticity of legal acts (Lei nº 8.935/1994, art. 6º) Lei nº 8.935/1994, art. 6º. For this reason, both document authentication and signature verification require strict compliance with legal formalities established in the rules of the Internal Affairs of Justice (Corregedorias de Justiça) and the Conselho Nacional de Justiça (CNJ) [National Council of Justice].

What are the modalities of signature verification at the notary office?

Brazilian legislation and regulatory standards divide the notarial act of handwriting verification into two modalities with distinct procedures, requirements, and degrees of certainty: signature verification by similarity (por semelhança) and signature verification by authenticity (por autenticidade). To understand the regulatory framework of this matter in detail, you can consult the guide on the limits of signature verification by similarity and authenticity.

Signature verification by similarity (Reconhecimento de firma por semelhança)

Signature verification by similarity occurs when the notary or clerk compares the graphic stroke on the private document with the signature deposited on the autograph card (signature card or ficha de firma) archived at the notary office. For this act to be performed, it is not mandatory for the person who signed to be present at the notary office at the time of the request.

The procedure of verification by similarity involves the following aspects:

• Notarial handwriting examination: The clerk analyzes the structural elements of the signature on the document (slant, graphic strokes, pressure, and speed) and compares them with the pattern previously registered on the signature card.
• Affixing the notary seal: If there is satisfactory visual and graphic correspondence, the clerk declares that the signature is similar to the one on file at the notary office.
• Indication of the verification type: The notary stamp or label must transparently state that the act was performed under the "by similarity" modality, without the presence of the signatory.

There are cases in which the registered signature is outdated due to the passage of time or changes in the citizen's handwriting. In these situations, the notary office may require an update of the signature card before performing the act, aiming to safeguard the legal certainty of document authentication and signature verification.

Signature verification by authenticity (Reconhecimento de firma por autenticidade)

Signature verification by authenticity offers the maximum level of certainty regarding the authorship of the signature. In this modality, the signatory citizen must appear in person at the notary office, equipped with an original official photo identification document, and sign the paper directly in the presence of the notary or the designated clerk.

The essential characteristics of verification by authenticity are:

• Rigorous personal identification: The clerk performs documentary verification of the signatory, checking the photograph, registration number, and validity of the identity document.
• In-person signature: The citizen signs the private document in the physical presence of the notary or clerk, or declares before them that the signature already affixed is of their own authorship.
• Signing the term book: The interested party signs the Term of Verification by Authenticity (Termo de Reconhecimento por Autenticidade) in the notary office's specific register book, binding their presence to the act performed.
• Affixing the specific seal: The notary seal will expressly indicate that the signature was verified by authenticity.

This modality is required by legal or regulatory norms in legal transactions of significant financial or personal impact, where the legal system prohibits verification by mere similarity.

How does opening and maintaining a signature card work at the notary office?

Opening an autograph card (cartão autógrafo) — commonly referred to as "opening a signature card" (abertura de firma) — is a preliminary and mandatory step for the notary office to provide the service of verification by similarity. Without a properly registered and updated signature card, the clerk lacks a documentary benchmark to compare and attest to the citizen's handwriting.

The procedure for opening and maintaining a signature card at the notary office involves the following operational steps:

• Presentation of an official identity document: The applicant must present a valid original photo ID (such as an Identity Card issued by State Public Security Secretariats, National Driver's License [CNH], or passport). Laminated photocopies, damaged documents, cards with old photos preventing clear identification, or expired documents (where applicable) are not accepted for opening the record.
• Presentation of the Individual Taxpayer Registry (CPF): The CPF number is required to link the notarial record to national identification systems.
• Completion of the signature card form: The citizen fills out the physical or digital card of the notary office, providing complete personal details, including full name, nationality, marital status, profession, domicile, telephone number, and email address.
• Collection of standard signatures: The citizen signs two or three times on the signature card. These signatures will serve as the comparison matrix (control pattern) for all future signature verifications by similarity.
• Biometric and photographic capture (where applicable): In accordance with the rules of Provimento CNJ nº 149/2023 [CNJ Provision No. 149/2023] issued by the Conselho Nacional de Justiça (CNJ) Provimento CNJ nº 149/2023, Livro II, notary offices may collect fingerprint biometrics and digital photographs to integrate into the notarial database and prevent identity fraud.

Opening a signature card does not have an expiration date fixed by federal law, but the Codes of Norms of regional Judicial Internal Affairs recommend updating the signature pattern periodically or whenever there is a noticeable change in the holder's handwriting.

When signature verification needs to be performed at a notary office where the citizen does not have an open signature card, the public signal (sinal público) procedure can be used. Through this inter-notarial communication, the origin notary office transmits the signature pattern of its clerk or the citizen's card to the office where the act is being performed, ensuring the national validity of the notarial act (Provimento CNJ nº 149/2023, Book I) Provimento CNJ nº 149/2023, Livro I.

With technological advancements in notarial services regulated by the Conselho Nacional de Justiça (CNJ) and Lei nº 14.382/2022 [Law No. 14,382/2022] Lei nº 14.382/2022, art. 3º, signature registration and visual verification have also extended digitally. To deepen your understanding of acts performed via videoconferencing and electronic means, consult our article on electronic notarial acts on e-Notariado and the analysis on signature validation and digital authentication.

What are the requirements for authenticating document copies?

The authentication of document copies is the notarial act by which the notary or clerk attests that the presented reprographic copy matches exactly the exhibited original document. It is an act endowed with public faith, generating the legal presumption that the copy carries the same evidentiary weight that the original document would have in court or before public agencies (Código Civil [Civil Code], art. 215) Lei nº 10.406/2002 — Código Civil, art. 215.

For the notary office to perform document authentication safely and regularly, specific formal and legal requirements must be strictly observed.

Mandatory requirement of the original document

It is legally impermissible to perform document authentication from another copy that has already been authenticated (so-called "authentication of a copy of a copy"), except in exceptional cases expressly provided for in local Codes of Norms. The general rule requires the clerk to physically handle the original matrix document.

The presented original document must meet the following soundness conditions:

• Physical integrity: It must not contain erasures, erased sections, chemical washes, perforations concealing text, cuts in qualification areas, or any indication of material tampering.
• Legibility: Typographic or handwritten characters must be perfectly legible, without smudges preventing unequivocal reading of parties, dates, and obligations.
• Textual continuity: If the document consists of multiple pages, it must demonstrate logical, formal, and textual continuity across sheets.

If the original document contains erasures or amendments not formally declared within the text prior to the issuing parties' signatures, the notary office will refuse document authentication or place an express reservation on the authentication stamp indicating the anomaly observed in the original matrix.

Limitations and prohibitions in document authentication

Notarial practice expressly prohibits the authentication of documents when the original text violates public order, morality, or contains null elements under civil law (Código Civil, art. 166) Lei nº 10.406/2002 — Código Civil, art. 166. Likewise, papers written in pencil or containing erasable essential parts are not accepted for creating authenticated copies.

Document verification also encompasses inspecting its completeness. An applicant cannot request the authentication of only half a page or an out-of-context excerpt that alters the meaning of the original statement, ensuring that the act of document authentication and signature verification maintains indispensable evidentiary fidelity.

When is in-person signature verification (por autenticidade) mandatory?

The choice between signature verification by similarity and by authenticity is not entirely discretionary for parties involved in a legal transaction. In various situations, the federal legal order or administrative regulations issued by the Conselho Nacional de Justiça (CNJ) mandate signature verification by authenticity as an indispensable condition for the acceptance or formal validity of a private document Lei nº 10.406/2002 — Código Civil, art. 104.

The compulsory requirement of verification by authenticity aims to mitigate risks of impersonation fraud and to ensure that the declarant has full awareness and agreement regarding the legal effects of the document being signed.

The requirement of signature verification by authenticity for specific acts not described in this general norm depends on special legislation or specific administrative rules not covered in this normative excerpt. Where the law is silent, the requirement for verification by authenticity may arise from a convention freely agreed upon by the parties in a private contract.

On the other hand, when the law requires a solemn formality under penalty of nullity — as occurs in the transfer of real property rights valued above 30 times the highest minimum wage — mere signature verification on a private instrument does not replace the necessity of executing a public deed (escritura pública) at a notary office Lei nº 10.406/2002 — Código Civil, art. 108.

Non-compliance with the requirement for verification by authenticity when mandated by express norms prevents the acceptance of the instrument by public agencies, boards of trade, or real estate registries, requiring the re-execution of the notarial act under the correct in-person modality.

Document checklist

To perform document authentication and signature verification procedures at the notary office, make sure to gather the recommended documentation below:

• [ ] **For opening or updating a signature card (ficha de firma):**
• Valid original official photo ID document (RG, CNH, Passport, or Professional Class Council Card) in good physical condition.
• Individual Taxpayer Registry card (CPF) or official document containing the CPF number.
• Updated proof or statement of residential address.
• [ ] **For signature verification by similarity (por semelhança):**
• Original private instrument with the signature already affixed by the holder who has an active signature card at the notary office.
• Prior verification that the document contains no uncancelled blank spaces or erased text.
• [ ] **For signature verification by authenticity (por autenticidade):**
• Valid original official photo ID of the signatory who will sign the document.
• Private instrument where the signature will be verified by authenticity (the document may be signed at the counter before the clerk).
• Mandatory physical presence of the signatory at the notary office to execute and sign the term book.
• [ ] For authenticating document copies:
• Complete original document, free of erasures, cuts, or material tampering.
• Legible reprographic copy of the original document (if the copy is not made directly by the notary office itself).

In practice

Case 1: Doubt regarding authentication of a simple copy of a private contract

Situation: A citizen visited the notary office carrying a simple photocopy of a service agreement and requested the clerk to authenticate that paper. He did not bring the original contract, claiming that the original remained with the other contracting party.

Notarial resolution: The clerk informed that notarial legislation prohibits authenticating documents without the simultaneous presentation of the original and intact matrix document (Lei nº 8.935/1994, art. 6º) Lei nº 8.935/1994, art. 6º. Granting public faith to a copy based on another simple or isolated authenticated copy is not permitted. The citizen was advised to obtain the original document from the other party or request an official certificate so that the notary office could perform the reprographic comparison and complete the authentication with legal certainty.

Case 2: Presentation of a private document for signature verification with a divergent signature

Situation: A company presented a private declaration at the notary counter for signature verification by similarity of one of its directors. Upon conducting a handwriting examination in the office's system, the clerk observed that the standard signature card on file dated back over fifteen years and showed substantial differences in inclination and stroke dynamics compared to the signature affixed to the recent document.

Notarial resolution: In light of the duties of prudence and fraud prevention, the clerk refused immediate placement of the similarity seal. The director was notified to appear at the notary office to update his autograph card (opening a new signature pattern) by presenting an updated identity document. Following re-registration and deposit of the new graphic pattern, the signature affixed to the private instrument was verified and validated through the similarity modality.

Common errors

• Requesting document authentication without bringing the original copy: The notary office is legally prohibited from authenticating reprographic copies without physically examining the original document.
• How to avoid: Always bring the printed original document in perfect condition to the notary counter.
• Pre-signing a document requiring verification by authenticity outside the clerk's presence: Signing a document at home when law requires in-person verification can lead to refusal if the citizen cannot confirm authorship in person at the counter.
• How to avoid: In cases where verification by authenticity is mandatory, prefer signing the document directly at the notary office in front of the clerk.
• **Leaving the signature card (ficha de firma) outdated for long periods:** Changes in handwriting over time or legal name changes due to marriage/divorce not reflected on the card prevent verification by similarity.
• How to avoid: Periodically visit the notary office to update your signature card and present recent identity documents.
• Presenting an original document with erasures or cut sections for authentication: The clerk cannot authenticate copies of originals containing uncorrected visible alterations or lacking physical integrity.
• How to avoid: Keep your original documents preserved from moisture, tears, and unauthorized alterations.
• Confusing signature verification with executing a public deed: Believing that signature verification on a private real estate purchase contract of high value replaces the public deed required by art. 108 of the Civil Code (Código Civil, art. 108) Lei nº 10.406/2002 — Código Civil, art. 108.
• How to avoid: For transactions involving real estate rights above the legal threshold, consult the notary office to execute the appropriate public deed.

Legal basis

• Lei nº 8.935/1994, art. 1º Lei nº 8.935/1994, art. 1º — Defines that notary and registration services are organized to guarantee publicity, authenticity, security, and effectiveness of legal acts Planalto.
• Lei nº 8.935/1994, art. 6º Lei nº 8.935/1994, art. 6º — Establishes the exclusive competence of notary publics to formalize the will of parties, authenticate facts, and verify signatures Planalto.
• Lei nº 10.406/2002 — Código Civil, art. 215 Lei nº 10.406/2002 (Código Civil), art. 215 — Establishes that notarial acts endowed with public faith provide full proof of the facts attested therein Planalto.
• Lei nº 10.406/2002 — Código Civil, art. 104 Lei nº 10.406/2002 (Código Civil), art. 104 — Addresses the validity requirements of legal transactions and compliance with forms prescribed by law Planalto.
• Lei nº 10.406/2002 — Código Civil, art. 166 Lei nº 10.406/2002 (Código Civil), art. 166 — Stipulates causes of nullity of legal transactions when essential formalities are omitted Planalto.
• Lei nº 14.382/2022, art. 3º Lei nº 14.382/2022, art. 3º — Provides for the modernization of the electronic registration and notarial system Planalto.
• Provimento CNJ nº 149/2023, Livro II Provimento CNJ nº 149/2023, Livro II — Consolidation of National Internal Affairs of Justice rules regarding notary services CNJ.
• Provimento CNJ nº 149/2023, Livro I Provimento CNJ nº 149/2023, Livro I — General guidelines for supervision and public signal acts in out-of-court services issued by the Conselho Nacional de Justiça (CNJ).

Frequently asked questions

What is the difference between document authentication and signature verification?

Document authentication attests that a reprographic copy is identical to the presented original document. Signature verification confirms the authorship of a signature affixed to a private document, guaranteeing its origin.

What are the modalities of signature verification at the notary office?

There are two main modalities at the notary counter: verification by similarity (por semelhança), when the signature is pre-written and compared with the autograph card, and by authenticity (por autenticidade), when the person signs in person before the notary or clerk.

How does opening and maintaining a signature card work at the notary office?

Opening a signature card (abertura de firma) is registering a person's details and signature at the notary office. The physical or digital signature card is stored to serve as a baseline for future verifications by similarity.

What are the requirements for authenticating document copies?

You must present the complete original document without erasures, alterations, or illegibility, accompanied by the corresponding reprographic copy for the clerk to inspect thoroughly before placing the seal.

When is in-person signature verification (por autenticidade) mandatory?

Verification by authenticity is required whenever special legislation establishes this compulsory formality to validate a legal transaction, or when the nature of the act requires a higher degree of certainty regarding authorship.

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Editorial Team of the 5th Notary Office of Recife (5º Tabelionato de Notas do Recife)

Notarial Service for Legal Certainty and Rights Protection

Date of last legal review: August 29, 2026

Version: 2.1 — In compliance with the PEAN Editorial Constitution (Protocolo Editorial Agêntico Notarial).

Informational and institutional content produced based on federal notarial legislation and Judiciary provisions. It does not replace direct consultation with a notary office for document analysis of specific cases.

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