Electronic signature vs. digital signature — which one do you need?

Two terms get used interchangeably, and the confusion has real consequences: people either over-engineer a lunch-order approval or under-protect a purchase agreement. Let's separate them.

Electronic signatures

An electronic signature is any mark applied electronically with the intent to sign: a typed name, a drawn squiggle, an uploaded image of your handwritten signature, a checkbox next to "I agree". In most jurisdictions — under the U.S. ESIGN Act, the EU's eIDAS regulation and similar laws elsewhere — a simple electronic signature is legally valid for the vast majority of everyday agreements, provided the parties intended to sign and the document can be shown to be the one they agreed to.

What it does not do on its own is prove who placed it or that the document was not changed afterwards. That evidence comes from context: the email thread, the timestamp, the counter-signature, your own records.

This is exactly what PDFCraft's Sign PDF tool produces. You draw, type or upload a signature, place it on one or more pages, and the tool embeds it as part of the page content. The result is a normal PDF that opens anywhere; there is no proprietary wrapper and nothing to verify online. The tool runs entirely in your browser, so the signed contract never leaves your device.

Digital signatures

A digital signature is a cryptographic construct. The signer holds a private key tied to a certificate issued by a certificate authority; the PDF stores a hash of the document encrypted with that key, plus the certificate chain. A reader such as Acrobat can then verify two things mathematically: the signature was created with the key belonging to that certificate, and not a single byte of the signed content has changed since.

Digital signatures are what "qualified electronic signatures" under eIDAS, notarised filings, many government submissions and some regulated industries require. Creating one needs a certificate — either a personal one on a smart card or USB token, or one issued by a signing service — and a signing tool that handles the PDF signature dictionary and timestamping.

PDFCraft does not create digital (certificate-based) signatures. We say this plainly because some tools blur the line by drawing a "verified" badge next to an image. A picture of a signature with a green tick is still a picture.

Which do you need?

Use a visible electronic signature when:

• the other party knows you and expects your signature (offers, NDAs between businesses, internal approvals, consent forms);
• the document is exchanged over a channel that already establishes identity, such as a company email account;
• no law or counterparty policy requires a qualified or certificate-backed signature.

Use a digital signature when:

• a regulation, court, public authority or the contract itself calls for a qualified or advanced electronic signature;
• the document's integrity must be verifiable years later by people who were not part of the conversation;
• you are signing on behalf of an organisation that has a signing policy and issued certificates.

Practical tips for e-signing PDFs

1. Flatten what you can. A signature embedded in the page content, as Sign PDF does, is harder to accidentally move or delete than an annotation.
2. Keep the original. Store the unsigned PDF and the signed one together with the email that sent it.
3. Add the date. Use the PDF editor's text tool to write the date next to your signature; it is the single most useful piece of context in a dispute.
4. Protect the signed file if it will travel: Protect PDF can disable editing so casual modification is discouraged (remember that permission flags are enforced by viewers, not by mathematics).
5. Don't sign what you haven't read. Obvious, and still the most common problem.