Electronic signature vs digital signature is a confusing pair, because the two names sound like one thing. They are two different things. An electronic signature is a mark that shows you agree to a document. A digital signature is a piece of cryptography attached to the file. A PDF can carry either, or both.
Electronic signature vs digital signature, in short
- An electronic signature is about intent. It is your name on the page, put there to say yes.
- A digital signature is about the file. It is made with a certificate, and it lets a reader check whether the document has changed since it was signed.
A digital signature is one way of signing electronically, so every digital signature is also an electronic one. It does not work the other way round: a drawn signature is not a digital signature.
What an electronic signature is
An electronic signature is any mark made on a screen that stands for your agreement. In a PDF that usually means one of three things: a signature drawn with a mouse or a finger, a name typed in a handwriting font, or a picture of the signature you write on paper.
All three end up as something you can see on the page. None of them involves a certificate, and nothing in the file checks who put the mark there or whether the text around it changed later. It is the on-screen version of signing a printout.
That is enough for a great many everyday documents, and it is quick: you can e-sign a form in a minute without printing anything.
What a digital signature is
A digital signature is made with a private key that belongs to a certificate. The software calculates a fingerprint of the file's bytes and seals it with that key. The seal and the certificate are stored inside the PDF.
Afterwards, a reader that supports digital signatures can do two things. It can recalculate the fingerprint and see whether the file still matches, so a change made after signing shows up. And it can look at the certificate to see who it was issued to, and whether it trusts whoever issued it.
A digital signature PDF often shows a visible signature box as well, but the box is decoration. The part that matters is the seal you cannot see.
Electronic signature vs digital signature: which one do you need?
It depends on who is asking, and this page cannot tell you what a particular contract, office or country requires. The requirements differ from one situation to the next, and they are set by whoever receives the document or by the rules that apply where you are. If you are not sure, ask the person who sent it.
As a rough guide to what people mean:
- If you were told to “sign and return” a form, a visible signature on the page is usually what is expected.
- If you were told the document must be “digitally signed”, “signed with a certificate” or signed through a named signing service, a drawn signature will not meet that, however good it looks.
Which one OpenPdfEdit makes
In terms of electronic signature vs digital signature, OpenPdfEdit, a free open source PDF editor, makes the first kind. You draw a signature, type your name or load a picture, and place it on the page as a visible mark. The sign a PDF page describes the tool, and how to add a signature to a PDF has the steps.
It does not create digital signatures. It has no certificates and does no cryptographic signing.
It does not verify them either. When a document already has digital signatures, the app lists what the document itself declares about each one: the signature format, and the name, reason and signing time the signer supplied. It also checks that the signed byte range has the shape a well-formed signature must have. That is a list of claims. It does not prove that a signature is valid, trusted, or tied to the bytes it says it covers, and the app labels it as not cryptographically verified. To verify a digital signature, use software that checks certificates.
Adding markup to a document that is already digitally signed
A digital signature covers the bytes of the file as they were when it was made. So what matters is how an edit is saved.
OpenPdfEdit saves a highlight, a note or a placed signature by appending the change to the end of the file. The bytes the existing signature covers are not touched. Some edits cannot be saved that way. Redaction rewrites the whole file, on purpose, and a rewrite breaks an existing digital signature. Both ways of saving are explained in two ways to save a PDF.
FAQ
Is an electronic signature PDF the same as a digitally signed PDF?
No. An electronic signature PDF has a visible signature on the page. A digitally signed PDF has a certificate-based seal inside the file, which a reader can check. That is the whole of electronic signature vs digital signature: a mark on the page, or a seal on the file.
Can I tell which one a PDF has?
Open it in a reader that supports digital signatures. A digitally signed document shows a signature panel or a banner about its signatures. A drawn signature is simply part of what you see on the page.
Does OpenPdfEdit make digital signatures?
No. It places a visible electronic signature on the page. It does not create or verify certificate-based digital signatures.
Which one should I use?
Whichever the recipient asks for. When you weigh electronic signature vs digital signature for a real document, the deciding question is what the other party, or the rules that apply to you, require.