Electronic signature vs digital signature: the difference

The two terms get used as synonyms, including by e-signature vendors, and that causes real confusion when a client's legal team asks for "a digital signature". This page sits in our contracts and signatures section; the legal status of both in the US and EU is covered in are electronic signatures legal?.

The difference in one table

What the law calls an electronic signature

The federal ESIGN Act defines an electronic signature as an electronic sound, symbol or process attached to or logically associated with a record and executed or adopted by a person with the intent to sign it (15 U.S.C. § 7006). Nothing in that definition requires cryptography. The question a court asks is whether this person intended to sign this record, and the answer comes from the evidence: the email the link went to, the consent screen, the timestamps.

In the EU, eIDAS uses the same broad idea for a simple electronic signature and then adds two levels. An advanced electronic signature (article 26) must be uniquely linked to the signer, capable of identifying them, created with data under their sole control, and linked to the document so that any later change is detectable. A qualified signature is an advanced one made with a qualified signature creation device and a qualified certificate; article 25 gives it the same legal effect as a handwritten signature across member states.

What a digital signature does technically

A digital signature works with a key pair. The signing software computes a hash of the document and transforms it with the signer's private key. Anyone with the matching public key can check two things: that the signature was made with that private key, and that the document hasn't changed since. A certificate from a certificate authority ties the public key to a named person or company. NIST's FIPS 186-5, published February 3, 2023, is the US federal standard; it approves RSA, ECDSA and EdDSA and keeps the older DSA only for verifying existing signatures.

Examples: which one is this?

• You type your name at the bottom of an email that says "I accept the quote": electronic signature, no cryptography.
• A client draws their signature on a contract through an e-signature tool that emails them a private link and records their IP and the time: electronic signature with an audit trail.
• You sign a PDF in Acrobat with a certificate stored on your computer: digital signature, which is also an electronic signature.
• A Mexican taxpayer signs a filing with the SAT's e.firma: a certificate-based advanced electronic signature (firma electrónica avanzada).

Which one does a freelancer need?

For a services contract, an NDA or a statement of work with a US client, a simple electronic signature with a good audit trail is the norm. Ask for something stronger when the client's own policy requires it, when a law names an advanced or qualified signature for that document type (some EU and Latin American filings do), or when you sign for a government agency. If a client asks for a "digital signature", ask what they mean: often they just mean "signed online".

What SoloWOS uses

SoloWOS E-Signatures provides simple electronic signatures. Signers consent to sign electronically, then draw or type their signature from a private email link. Every step is logged with time, IP and device in a certificate of completion, and the certificate records SHA-256 fingerprints of the original and the signed PDF. Anyone can recompute the fingerprint of the file they hold and compare. That makes changes detectable, but it isn't a certificate-based digital signature, and SoloWOS doesn't offer advanced or qualified signatures. Learn how to send PDFs for e-signature, what the audit trail records, and how the rules work with clients abroad.