In today’s digital identification landscape, one thing is clear: there are many ways to sign electronically, each with its own distinct characteristics. These range from more advanced methods, such as qualified electronic signatures, to more streamlined methods, such as custom fields (evidence). With their own unique features, each method relies on different mechanisms: the digital certificate and the digital signature. However, these concepts continue to raise questions, and it’s common to think they’re synonymous.
For that reason, in this article, we’ll explain the differences between digital certificates and digital signatures, provide a detailed definition of each, and show you how you can leverage them in your business.
Difference Between a Digital Certificate and a Digital Signature: What Is Each One?
One of the most common misconceptions among the general public is the belief that “digital certificate” and “digital signature” are synonymous. For this reason, it’s essential to understand their characteristics and differences in order to use each one correctly.
What Is a Digital Certificate?
A digital certificate is an electronic file issued by a Trusted Authority or Certification Authority (CA) that uniquely links to and identifies a person or entity. In practice, it can be thought of as your digital ID—a file designed to unequivocally verify your identity online so you can safely complete online transactions.
To obtain one, you must contact a Qualified Service Provider (QSP), a natural or legal person that provides one or more of the following services:
- Creation, verification, and validation of electronic signatures, seals, time stamps, certified electronic signature services, and certificates related to these services
- Creation, verification, and validation of certificates for website authentication
- Protection of electronic signatures, seals, or certificates related to these services
In Spain, one of the most widely used Qualified Service Providers is the one issued by the National Mint and Stamp Factory (FNMT), although there are other internationally recognized entities.
When a digital certificate is issued to third parties, TSPs or CAs can provide the following security benefits:
- Personal information to unequivocally identify the owner;
- Information necessary for identification and communication with the authority that issued the document;
- Designed to be resistant to tampering and forgery;
- Issued by an agency that can revoke an identification card at any time (for example, if the card is used for other purposes or is lost);
- Its authenticity can be verified by contacting the issuing authority.
Digital certificates have become essential for communicating with the private sector and, above all, with the government, making it possible to complete administrative procedures from any computer or mobile device.
What Is a Digital Signature?
It is a cryptographic mechanism that guarantees the authenticity and integrity of an electronic document, ensuring that it has not been altered after validation.
Principles of Digital Signatures
A few years ago, the European Union introduced a law to regulate electronic signatures, as well as the characteristics they must include to be legally valid:
- Authentication of origin: Allows the person responsible for the document to be identified with certainty.
- Non-repudiation: The person who validates the document cannot deny having done so.
- Integrity: Guarantees that the content has not been modified after validation.
| Identification mechanism | Digital certificate | Digital signature |
| Nature | It is an electronic identity file | It is the act of signing or the technical result |
| Purpose | To authenticate who you are | To sign a document |
| Expiration | It has an expiration date | The signature on the document is permanent; it does not expire |
| Analogy | Your digital ID | Your signature on a piece of paper or document |
Essentially, this mechanism is used in various sectors to streamline processes and ensure the validity of electronic documents.
Types of Electronic Signatures and Legal Validity
EU legislation, technically known as EU Regulation 910/2014 and commonly referred to as the eIDAS Regulation, has become the benchmark legislation on electronic signatures. It also establishes three types of electronic signatures:
- Simple electronic signature: A simple electronic signature is defined as data in electronic form that is attached to or logically associated with other data in electronic form and is used by the signatory to sign. It has legal effect and is admissible in court, although it may need to be supported by other types of evidence.
- Advanced electronic signature: Created using signature data that only the signatory can use, with a high level of confidence, under the signatory’s exclusive control, and linked to the data signed by the signatory so that any subsequent changes can be detected. This type of signature certifies the signatory’s identity and the integrity of the data, providing greater legal guarantees.
- Qualified electronic signature: This is an advanced electronic signature created using a qualified electronic signature creation device and based on a qualified certificate. It offers the highest possible level of security and has the same legal effect as a handwritten signature.
Digital Certificate vs. Digital Signature: Which Should You Use?
Choosing one option over the other depends on several factors, such as how often you sign documents, the type of document, or who the other party is. To help you decide, we’ve created a comparison that covers some of the most common business situations.
| If your situation is… | The ideal solution is | Practical example |
| Dealing with government agencies | Digital certificate | Filing your income tax return |
| Automating agreements | Digital signature software | Sending a service contract to a client |
| HR and employee onboarding | Digital signature software | Bulk sending of employment contracts, pay stubs, or non-disclosure agreements (NDAs) |
Other Validation Methods in the Workplace
Once you understand the differences between a digital certificate and a digital signature, keep in mind that, by 2026, companies and customers will no longer have to go through complex setup processes on their computers. Instead, there are other validation methods that may be useful depending on the circumstances and the documents to be signed:
- OTP (One-Time Password) Signature: The user receives a code to validate the document in seconds.
- Centralized (Cloud) Signature: Securely stores your company’s certificates in the cloud from any location, without the need for specific devices.
Legally Binding Electronic Signatures for Your Business
Viafirma covers all the signing options mentioned above, adding extra layers of security such as time stamping and electronic evidence. Thus, our digital solutions—including our electronic signature software—are designed so you don’t have to choose between security and convenience.
Whether through a digital certificate or an electronic signature, we help your company go paperless, reduce costs, and ensure that your documents are legally unassailable.