Electronic Signature vs Digital Signature: The Difference
Someone asks for a “digitally signed” copy. You draw your name on the PDF and send it back. They reject it.
The two terms get used as though they mean the same thing, including by people who should know better, and most of the time the sloppiness costs nothing. When it costs something, it costs a rejected filing or an unenforceable agreement — so it is worth ten minutes to understand which one you have.
The distinction in one line
An electronic signature is any mark you apply to show intent. A drawn squiggle, a typed name, a tick in a box, a photographed signature, a line at the bottom of an email.
A digital signature is a cryptographic operation using a private key and a certificate. Validation checks the signed revision and certificate trust; a certificate can be self-signed, so its presence alone does not prove that an independent authority verified the signer’s identity.
The first is about intent. The second is about proof. Every digital signature is a kind of electronic signature; almost no electronic signature is a digital signature.
What each one actually is
The electronic signature
A picture placed on a page. When you draw your name in Sign PDF, the result is an image laid onto the page like any other graphic, and after export it is page content in exactly the way printed text is.
That has a specific consequence worth stating: a visible signature carries no information about who made it. The file does not know. The image could be drawn by anyone, copied from another document, or lifted from a photograph. It shows that a signature was placed. It does not show by whom.
For most documents that is entirely adequate, because the surrounding context does the work the signature does not — you emailed it from your address, in a thread where the terms were agreed, to someone who knows you.
The digital signature
Not a picture. A number, computed from the entire contents of the document together with a private key that only you hold.
Three properties follow, and they are the whole point:
- Integrity. Altering bytes covered by the signature breaks its cryptographic check. A signature-aware application may append permitted revisions, such as another signature, without replacing the signed revision.
- Authenticity. The signature ties to a certificate and its public key. Identity assurance depends on certificate issuance, trust settings, and the verification process.
- Non-repudiation. Because only you hold the private key, it is very hard to credibly claim you did not sign.
A digital signature does not need to be visible at all. When you see a signature panel in a PDF reader saying the document is signed and valid, that panel is reporting a verification result, not describing a picture.
Side by side
| Electronic signature | Digital signature | |
|---|---|---|
| What it is | An image or mark on the page | A cryptographic seal over the file |
| Identity evidence | Depends on the signing process | Depends on certificate trust and issuance |
| Detects changes | No cryptographic check in a placed image | Checks signed bytes and subsequent revisions |
| Needs a certificate | No | Yes |
| Later editing | Appearance may remain; review the result | Depends on the change and signature permissions |
| Verifiable by the reader | No | Yes, automatically |
| What this site produces | Yes | No |
That last row is why this guide exists on this site. Sign PDF produces the left-hand column, and pretending otherwise would be the most consequential thing we could get wrong.
Both are usually legally valid, and that surprises people
The instinct is that only the cryptographic one “counts”. That is not how the law generally works.
In the United States, the Electronic Signatures in Global and National Commerce Act provides that a signature or contract may not be denied legal effect merely because it is electronic. Most developed jurisdictions have comparable legislation. A typed name at the bottom of an agreement can bind you.
So the practical question is rarely is this valid — it is usually can I prove it, later, to someone who disputes it.
Neither appearance nor a certificate alone settles legal validity or a dispute. Acceptance depends on the document, jurisdiction, signing process, and retained evidence, so confirm the receiving party’s requirements before choosing a method.
This is general information, not legal advice. Most such laws carve out categories — wills, certain family and property matters, some notices — and regulated sectors impose their own requirements on top.
Which one do you need?
An electronic signature is fine for: internal approvals, routine commercial agreements, consent forms, invoices, delivery notes, engagement letters, NDAs between parties who know each other, and the great majority of documents that ask for a signature.
You need a digital signature when:
- The requirement says qualified, advanced, or certificate-based. Those are terms of art, and they mean cryptography.
- A court, regulator, tax authority, or bank specified it.
- The document is high-value enough that a dispute is realistic.
- You are one of several parties signing in sequence and each needs an independently verifiable seal.
- Long-term integrity matters — an archived record that must be provably unchanged in ten years.
The phrase signed PDF does not identify the required signature type. Ask whether the recipient accepts a visible mark or requires a particular certificate, trust provider, or independently verifiable signing process.
How to get a digital signature
This site adds visible signature images and does not implement certificate signing. Browser-based signing services can exist, but their identity, key-management, and data-handling processes must be assessed separately from this local image-placement tool.
The routes are: a certificate authority or trust service provider in your jurisdiction, a national digital identity scheme where one exists, a signing platform that issues certificates as part of its service, or your organisation’s IT department if it operates its own authority.
Depending on the service, signing keys may be held on a device, a token, or managed signing infrastructure. Use a workflow accepted by the recipient, and check the resulting signature in a reader that supports validation.
What breaks a signature
This trips people up constantly, so it is worth being concrete.
This site’s page-rebuilding exports do not preserve a valid signature over the new file. That is different from permitted changes to a certified PDF, such as allowed form filling or subsequent signatures saved by a compatible application.
So the order is fixed: finish the document completely, then sign it. Preparing a PDF bundle for submission sets out that sequence, and it is the same reason merging warns about signed inputs.
A visible signature survives all of it, because it is page content. It also proves correspondingly less — the two facts are the same fact.
How to tell what a document already has
Given a PDF someone sent you, you can usually work out which kind it carries in a few seconds.
Open it in a reader with signature validation. Inspect the signature panel, certificate trust, and any reported changes. A reader with no verification interface may show no banner even when the PDF contains a digital signature.
Try to select the signature. If the document has real text and the signature is a placed image, you can usually select the text around it but not the mark itself. That tells you it is page content — a picture.
Check whether the page is a picture too. On a scanned document nothing selects at all, and a signature there tells you only that someone signed the paper before scanning it. That is a photograph of a signature, evidentially weaker again — the diagnosis is the same one in why can’t I copy text from a PDF.
A verification banner that reports the signature is invalid is worth reading carefully rather than dismissing. It usually means the document was edited after signing, which is exactly what the mechanism exists to tell you.
Signatures, encryption, and passwords
Three separate things that get bundled together in conversation:
- A signature answers who approved this, and has it changed?
- Encryption answers who can open this? — see how to password-protect a PDF.
- Permission flags ask viewers to restrict printing or copying, and are honoured by convention rather than enforced.
Visible signature images can be added before this site’s password-protection export. For certificate signatures, arrange encryption and signing in a compatible workflow before the final signature, and validate afterwards; do not rebuild a digitally signed file here merely to encrypt it.
The format’s part in it
Signature fields, signature dictionaries, and certificate-based signing are all specified in ISO 32000-2, but signature validation and trust support vary by reader. The PDF Association publishes accessible reference material on the specification.
Standardized structures allow independent implementations to validate signatures, but not every PDF viewer implements that function. Check the document in the recipient’s actual reader and retain the original signed file when verification is important.