O digital certificate It functions as an electronic identity linked to a natural or legal person, while the digital signature is the cryptographic act applied to the document to prove authorship and integrity.
Thus, digital certificate and digital signature They combine complementary, but not equivalent, technologies: the certificate identifies the holder and associates their data with a public key; the signature uses the corresponding private key to produce verifiable evidence. In other words, this combination enhances security, reduces in-person steps, and supports the formalization of legally valid documents.
Summary
- The digital certificate represents the holder's electronic identity.
- A digital signature protects authorship, integrity, and proof of the act.
- The certificate is required to generate a qualified electronic signature.
- The choice of type, key safekeeping, and validation define the security of the process.
Quick facts
- As guidelines from the Federal Revenue Service They state that revocation renders the certificate invalid and prevents further use.
- A RFC 5280 describes the validation of the chain that links the holder's identity to the public key.
- As ENISA guidelines They note that, in the European Union, a qualified electronic signature has the same legal effect as a handwritten signature.
What is digital certificate?
A digital certificate is an electronic document issued by a certification authority after validating the applicant's identity. According to the National Institute of Information Technology, the definition of digital certification at ITI It links a person or entity to a pair of cryptographic keys. The public key can be distributed for verification, while the private key must remain under the exclusive control of the holder. ICP-Brazil structure It organizes this chain of trust in the country.
The certificate identifies, but does not sign on its own.
The certificate contains data that allows a public key to be linked to its holder, as well as information such as the issuer, purpose, and validity period. It can be used to authenticate access, represent a company in systems, and enable qualified signatures. e-CNPJ certificateFor example, it identifies a legal entity in compatible transactions. However, possessing the certificate does not mean that all documents are already signed: the signature only appears when the holder authorizes the use of the private key in a specific file.
What is digital signature?
A digital signature is a type of electronic signature based on asymmetric cryptography. The system calculates a mathematical summary of the document, called a hash, and uses the signer's private key to generate the signature. The content we produce about hash functions It helps to understand why any subsequent change produces a different result. According to the NIST standardDigital signatures allow for the detection of unauthorized modifications and the authentication of the identity attributed to the signatory.
Authorship, integrity, and non-repudiation
During verification, the public key associated with the certificate confirms whether the signature matches the holder's private key and whether the document remains intact. This upholds three properties: authorship, because it links the act to the signatory; integrity, because it reveals subsequent alterations; and non-repudiation, because it offers technical evidence that the signature was produced with the credential controlled by the holder. The comparison between digital and electronic signature It also shows that not all electronic signatures depend on an ICP-Brasil certificate.
Digital certificate and digital signature: differences and complementarity
The key difference lies in the role of each resource. The certificate proves who holds the credential; the signature records the cryptographic use of that credential on specific content. According to the Law No. 14.063 / 2020The certificate associates validation data with a person, while the qualified electronic signature uses a digital certificate and offers the highest level of reliability foreseen in the legal classification.
| Appearance | Electronic Certificates | Digital signature |
|---|---|---|
| main function | Identify the owner and link their public key. | Register authorship and protect the integrity of the document. |
| Time of use | In the authentication or provision of credentials | When the private key is applied to the content |
| Result | Verifiable electronic identity | Cryptographic evidence linked to the signed file |
| Dependency | It can be used for various digital operations. | In the qualified modality, it depends on an ICP-Brasil certificate. |
When is the certificate required?
A certificate is required when the law, public body, system, or internal policy demands a qualified electronic signature or certificate-based authentication. Law No. 14.063/2020 provides for this modality in specific situations, such as certain electronic invoice issuances and acts of transfer and registration of real estate. In private relationships, the appropriate level depends on the risk, regulatory requirements, and acceptance by the parties. The analysis should consider the type of document, the impact of a dispute, and the need for interoperability.
How do I sign a document with a digital certificate?
The workflow combines technical preparation, authorization from the data subject, and validation of the result. Execution can occur on a compatible signer, on an integrated platform, or through a... cloud certificate...depending on the type of contract and the requirements of the process.
- Choose the certificate: Define whether the identity will be personal or business-related, and whether the storage will be local, on a token, card, or in the cloud.
- Install or connect: Configure the drivers, application, or authentication required for the system to recognize the credentials.
- Select the document: Check the version, signatories, fields, and format before starting the signature process.
- Authorize its use: Provide a password, two-factor authentication, or other mechanism to control the private key.
- Validate the file: Confirm certificate, chain of trust, integrity, date, and signature status.
Password, private key, and expiration date precautions
The password should not be shared, and the private key must remain under the control of the holder or a formally authorized management entity. Tokens and cards should be kept in a secure location; archived certificates require protection against unauthorized copying; cloud solutions require strong authentication. It is also necessary to monitor expiration and revocation. Policies of signature compliance They help define responsibilities, access logs, incident response, and renewal criteria.
Business applications and performance indicators
Legal, sales, purchasing, human resources, and finance departments can use digital signatures for higher-risk contracts, powers of attorney, corporate documents, approvals, and regulatory obligations. The gains shouldn't be evaluated solely by replacing paper documents. The company needs to consider processing time, cost per document, completion rate, and percentage of successful validations. This data shows whether the workflow reduces rework, accelerates revenue, and maintains the expected level of security.
| KPI | How to measure | Decision supported |
|---|---|---|
| Formalization time | From preparation to closing the signing process. | Identify bottlenecks and delays. |
| Operating cost | Hours, systems, printing, sending and storage | Compare physical and digital processes. |
| Successful validations | Valid subscriptions apply to the total processed amount. | Detecting technical faults or inadequate certifications |
| Completion rate | Finalized documents regarding those sent. | Enhancing the signatories' experience |
Check out these related articles as well:
- Learn how to sign documents with a digital certificate..
- Check out the steps to verify the validity of your subscription..
- What are the costs of a business digital signature??
The right choice combines identity, security, and efficiency.
Certificates and signatures should be selected according to the document's purpose, risk level, and applicable legal requirements. The company reduces costs by avoiding redundant tools, minimizing travel, eliminating printing, and monitoring workflow indicators. Simultaneously, it preserves security by controlling credentials, validating files, and maintaining an up-to-date chain of trust.
By distinguishing between electronic identity and cryptographic act, the organization better chooses the technology, documents responsibilities, and reduces the risks of misuse. The certificate identifies the holder; the signature records their statement about verifiable content. This understanding makes the relationship between digital certificate and digital signature A clearer framework for legal, operational, and financial decisions. To assess how this structure can be integrated into business journeys, learn more about... functioning as a Certification Authority.
Frequently Asked Questions (FAQ)
No. A digital certificate identifies a natural or legal person and links that identity to a public key. A digital signature is created when the corresponding private key is applied to a document. The certificate serves as a credential; the signature is the cryptographic evidence produced in a specific operation.
No. Brazilian law classifies electronic signatures as simple, advanced, and qualified. The qualified signature uses a digital certificate in accordance with ICP-Brasil standards. The other types may employ different means of identification and verification, provided they are appropriate to the context, accepted by the parties, and compatible with applicable legal requirements.
An expired certificate should not be used to generate new signatures. The validity of a signature already made depends on the verification of the certificate, the chain of trust, the time of registration, and other technical elements. Therefore, the company must validate the document and maintain evidence that allows its status to be analyzed at the time of signing.
The A1 card is usually stored as a digital file and integrated into compatible systems. The A3 card can be stored on a token, card, or in the cloud, with its own access mechanisms. The choice depends on mobility, integration, key control, frequency of use, and process requirements. Validity and characteristics should be confirmed with the issuing authority.
Validation verifies the integrity of the file, the correspondence between signature and certificate, the chain of trust, the validity period, and any revocation status. The result should be consulted in a tool compatible with the standard used. Changes to the document after signing may cause the verification to indicate inconsistency.
Getúlio Santos is the CEO of ZapSign, a lawyer, technology enthusiast, and entrepreneur.
