Digital Signature vs. Electronic Signature: Demystifying the Confusion

Although in everyday language —and even in some professional contexts— the terms digital signature and electronic signature are used interchangeably, they actually represent distinct technological and legal concepts, with clearly differentiated functions.

Understanding this distinction is not a matter of semantics: it is essential to guarantee the legal validity of agreements, document integrity, and their admissibility as evidence before third parties or courts.

Below we explain what each one is, how they complement each other, and why both are necessary in a solid legal-digital environment.

1. What Is an Electronic Signature? The Agreement

The electronic signature focuses on the signer’s intent. Its main function is to express a person’s consent regarding the content of a document, acting as the digital equivalent of signing a paper contract.

From a legal standpoint, regulations such as the eIDAS Regulation (EU) or the E-Sign Act (USA) define electronic signature as any process, data, or symbol associated with a document that a person uses with the explicit intention of signing.

What matters is not the format, but the intent.

Common Forms of Electronic Signature

There are multiple ways to express that consent, whose suitability depends on the level of risk and the applicable regulatory framework:

• Accepting terms via a button or checkbox.
• Drawing a signature on screen with a mouse or touch device.
• Signing via a link received by email or SMS.
• Authenticating with an electronic identity system.

All of these modalities can be legally valid if accompanied by sufficient evidence of who signed and under what conditions.

2. What Is a Digital Signature? The Security

The digital signature, by contrast, does not express intent or consent. It is a purely technical mechanism whose aim is to guarantee the integrity and authenticity of an electronic document.

It is based on cryptographic techniques (PKI, digital certificates, hash functions) and acts as a security seal applied to the final file.

Key Characteristics of the Digital Signature

• Unique fingerprint: Each document generates an unrepeatable digital signature.
• Proof of origin: It makes it possible to verify that the file comes from a legitimate source.
• Immutability: Any subsequent modification invalidates the signature.

It is important to stress that a digital signature does not encrypt the document nor does it replace archiving; it simply makes it possible to verify that the content has not been altered since it was sealed.

3. Key Differences: The Seal Analogy

A simple way to understand the difference is through a classic analogy:

• The electronic signature is equivalent to writing your name at the end of a letter. It represents your intention to accept its content.
• The digital signature is comparable to a wax seal placed on the closed envelope. It does not say who agrees, but it does guarantee that no one has tampered with the content.

While the electronic signature proves the agreement, the digital signature proves the technical authenticity of the document.

4. Why Both Are Needed for Legal Validity

For an electronic document to be solid from a legal standpoint, it must fulfil three essential principles, commonly known as the three I’s:

1. Intent: Clear evidence of the willingness to sign.
2. Identity: Ability to link the signature to a specific person.
3. Integrity: Guarantee that the document has not been modified.

The electronic signature covers intent and contributes to identifying the signer.
The digital signature ensures the technical integrity of the final document.

When both are correctly combined, the result is a legally enforceable document, independently verifiable and resistant to technical challenges.

In the absence of a digital signature, an electronically signed document could be altered without there being objective proof of that tampering. And without an electronic signature, a technically intact document would lack contractual value.

Frequently Asked Questions (FAQ)

Are digital signature and electronic signature the same thing?
No. The electronic signature expresses the signer’s consent; the digital signature guarantees the technical integrity of the document.

Can an electronic signature exist without a digital signature?
Yes, but it would offer fewer evidential guarantees in a dispute.

Does a digital signature alone create a valid contract?
No. The digital signature does not express intent; it needs to be accompanied by an electronic signature process.

What does the eIDAS Regulation require?
eIDAS recognises both concepts and establishes that their appropriate combination makes it possible to guarantee legal validity, integrity, and non-repudiation.

Conclusion

Confusion between digital signature and electronic signature is common, but their functions are complementary, not interchangeable. The electronic signature provides legal intent; the digital signature provides technical security.

Only when both work together do you obtain a truly robust electronic document, capable of withstanding audits, legal disputes, and the passage of time with full guarantees.