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is an electronic signature on a pdf legally valid

Is an electronic signature on a PDF legally valid?

Short answer: a signature image is a simple electronic signature. It may count between parties who accept it, but it does not prove authorship or integrity on its own, and there are cases where only a certificate or gov.br will do.

The law's three types and where this tool fits

Brazil's Law 14.063 of September 23, 2020 deals with the use of electronic signatures in dealings with public bodies, in acts of legal entities and in health matters. Article 4 sorts them into three. The simple one lets you identify the signer, or attaches or associates the signer's data with other electronic data. The advanced one uses certificates not issued by ICP-Brasil, or another means of proving authorship and integrity, provided the parties admit it as valid or the person against whom the document is used accepts it, and it must be uniquely tied to the signer, use data the signer controls exclusively and let any later change be detected. The qualified one uses an ICP-Brasil digital certificate, under article 10, paragraph 1, of Provisional Measure 2.200-2 of August 24, 2001.
A signature image pasted on a PDF, like the one this tool writes, falls in the lowest tier, the simple electronic signature. It does not bind the file to the signer by cryptography and does not let anyone detect a later change: anyone with a PDF editor can copy the image or alter the text. So its worth depends on the context, and the law itself, in article 5, leaves each federative entity to define the minimum level required in dealings with it. Article 10, paragraph 2, of MP 2.200-2 admits other means of proving authorship and integrity, including certificates outside ICP-Brasil, as long as the parties accept them. Between private parties who agree to use a signature image on a simple contract, the document may be accepted; in a dispute, whoever relies on it needs other evidence, such as emails, delivery records and witnesses.
When the requirement comes from the law, a public body, a notary office or a contract, use the official service. The federal government portal states that the gov.br electronic signature requires a silver or gold level account, and that its validity matches that of a document with a physical signature, under Decree 10.543/2020. The signing address is assinador.iti.br and verification of signed documents is validar.iti.gov.br; both are linked in the tool. Another practical point: if the PDF already carries a digital signature, writing an image on it breaks the earlier one, because the signature covers the file's bytes. The tool looks for the /ByteRange field and warns you first. When in doubt, ask whoever will receive the document which signature level they accept before you sign.

Which type is which

Signature image on the PDF (this tool)

Input: Imagem desenhada, digitada ou enviada
Expected output: Assinatura eletrônica simples (art. 4º, I)

It identifies visually, but proves neither authorship nor integrity.

Another means accepted by the parties

Input: Certificado fora da ICP-Brasil, aceito pelas partes
Expected output: Assinatura eletrônica avançada (art. 4º, II)

It requires a unique tie, exclusive control and change detection.

ICP-Brasil digital certificate

Input: Certificado A1 ou A3 da ICP-Brasil
Expected output: Assinatura eletrônica qualificada (art. 4º, III)

It has the highest level of reliability under the law.

PDF that already has a digital signature

Input: Arquivo com campo /ByteRange
Expected output: A ferramenta avisa: gravar invalida a anterior

Detection looks for the text /ByteRange in the file bytes.

Full tool FAQ

Are my signature and my PDF uploaded to a server?

No. pdf.js reads the PDF and pdf-lib writes it inside your browser, and the signature image never leaves the device. The signatures you choose to save live in this browser's localStorage, up to 24 images and 6 signers, and can be deleted one by one. Closing the tab discards the open document. Because nothing is uploaded, the tool is also fine for contracts and sensitive documents.

Does this signature have legal validity?

What is the difference from a certificate-based or gov.br signature?

How do I put initials on every page at once?

Can I sign with a photo of my signature on paper?

Which fonts can I use for a typed signature?

What happens if the PDF already has a digital signature?

Does it work with password-protected PDFs or forms?

Do signatures stay put on rotated pages or pages with different margins?

Is there a limit on size or number of items?

Frequently asked questions

Does my signature image count like a paper one?

It depends on who receives it. Between parties who agree, it may be accepted; before public bodies, notary offices or in contracts that require a qualified or advanced signature, it is not enough. This page is informational and is no substitute for legal advice.

How do I make a signature with formal validity?

Use the federal government's official service (assinador.iti.br, with a silver or gold gov.br account) or an ICP-Brasil digital certificate, and verify the file at validar.iti.gov.br. The tool links those addresses in the notice at the top.

Can I sign with this tool and then with gov.br?

Yes, in that order. First place the images and initials here, download the PDF and only then sign digitally in the official service. The reverse breaks the digital signature, because changing the file after it invalidates it.

Next steps

The law's three types and where this tool fits

Brazil's Law 14.063 of September 23, 2020 deals with the use of electronic signatures in dealings with public bodies, in acts of legal entities and in health matters. Article 4 sorts them into three. The simple one lets you identify the signer, or attaches or associates the signer's data with other electronic data. The advanced one uses certificates not issued by ICP-Brasil, or another means of proving authorship and integrity, provided the parties admit it as valid or the person against whom the document is used accepts it, and it must be uniquely tied to the signer, use data the signer controls exclusively and let any later change be detected. The qualified one uses an ICP-Brasil digital certificate, under article 10, paragraph 1, of Provisional Measure 2.200-2 of August 24, 2001.

A signature image pasted on a PDF, like the one this tool writes, falls in the lowest tier, the simple electronic signature. It does not bind the file to the signer by cryptography and does not let anyone detect a later change: anyone with a PDF editor can copy the image or alter the text. So its worth depends on the context, and the law itself, in article 5, leaves each federative entity to define the minimum level required in dealings with it. Article 10, paragraph 2, of MP 2.200-2 admits other means of proving authorship and integrity, including certificates outside ICP-Brasil, as long as the parties accept them. Between private parties who agree to use a signature image on a simple contract, the document may be accepted; in a dispute, whoever relies on it needs other evidence, such as emails, delivery records and witnesses.

When the requirement comes from the law, a public body, a notary office or a contract, use the official service. The federal government portal states that the gov.br electronic signature requires a silver or gold level account, and that its validity matches that of a document with a physical signature, under Decree 10.543/2020. The signing address is assinador.iti.br and verification of signed documents is validar.iti.gov.br; both are linked in the tool. Another practical point: if the PDF already carries a digital signature, writing an image on it breaks the earlier one, because the signature covers the file's bytes. The tool looks for the /ByteRange field and warns you first. When in doubt, ask whoever will receive the document which signature level they accept before you sign.

Which type is which

Signature image on the PDF (this tool)

Input: Imagem desenhada, digitada ou enviada
Expected output: Assinatura eletrônica simples (art. 4º, I)

It identifies visually, but proves neither authorship nor integrity.

Another means accepted by the parties

Input: Certificado fora da ICP-Brasil, aceito pelas partes
Expected output: Assinatura eletrônica avançada (art. 4º, II)

It requires a unique tie, exclusive control and change detection.

ICP-Brasil digital certificate

Input: Certificado A1 ou A3 da ICP-Brasil
Expected output: Assinatura eletrônica qualificada (art. 4º, III)

It has the highest level of reliability under the law.

PDF that already has a digital signature

Input: Arquivo com campo /ByteRange
Expected output: A ferramenta avisa: gravar invalida a anterior

Detection looks for the text /ByteRange in the file bytes.

Full tool FAQ

Are my signature and my PDF uploaded to a server?

Does this signature have legal validity?

What is the difference from a certificate-based or gov.br signature?

How do I put initials on every page at once?

Can I sign with a photo of my signature on paper?

Which fonts can I use for a typed signature?

What happens if the PDF already has a digital signature?

Does it work with password-protected PDFs or forms?

Do signatures stay put on rotated pages or pages with different margins?

Is there a limit on size or number of items?

Frequently asked questions