SignatureSmith / Electronic vs digital signature
Electronic vs digital signature
People use the words interchangeably, but they are different things. An electronic signature shows that you agreed. A digital signature proves, mathematically, who signed and that nothing changed afterwards. Try one for real below.
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How a digital signature works
The demo above uses the same building blocks as a signed PDF, via your browser's built-in Web Crypto API:
- Hash. The document is run through SHA-256, which turns any text into a 256-bit fingerprint. Change one character and the fingerprint changes completely.
- Sign. The fingerprint is signed with the private key using ECDSA on the P-256 curve (a NIST standard used widely on the web).
- Verify. Anyone with the public key can check that the signature matches the fingerprint of the document they received. If the document was edited, the fingerprints differ and verification fails.
A real signed PDF adds a certificate from a certificate authority that states whose public key it is, and usually a trusted timestamp.
The legal side, briefly
United States: the ESIGN Act of 2000 and the Uniform Electronic Transactions Act (adopted by 49 states) say a signature cannot be denied legal effect just because it is electronic.
European Union: the eIDAS regulation defines three levels. A simple electronic signature can be as basic as a typed name; an advanced one must be uniquely linked to the signer and detect changes; a qualified one uses a qualified certificate and device and has the same effect as a handwritten signature across the EU.
United Kingdom: the Electronic Communications Act 2000 and the Law Commission's 2019 report confirm electronic signatures are generally valid.
For ordinary paperwork, make an electronic signature with the signature generator and place it on your PDF. This page is general information, not legal advice.
Electronic and digital signature questions
What is the difference between an electronic signature and a digital signature?
An electronic signature is any electronic mark you use to agree to something: a typed name, a drawn signature image, a ticked box. A digital signature is a specific cryptographic technique that uses a private key and a certificate to prove who signed and that the document has not been changed since.
Is a digital signature the same as a scanned signature?
No. A scanned or drawn signature is an image; anyone with the file can copy it. A digital signature is a mathematical value calculated from the document and a private key, and it becomes invalid if the document changes.
How do I create a digital signature?
For a certificate-based digital signature you need a digital ID: a certificate issued by a certificate authority, a government eID card, or a self-signed ID created in software like Adobe Acrobat (Tools › Certificates › Digitally Sign). For everyday contracts, an electronic signature made with a signature generator is usually enough.
Are electronic signatures legally binding?
In the United States, the ESIGN Act (2000) and the Uniform Electronic Transactions Act give electronic signatures the same legal effect as handwritten ones for most transactions. In the EU, the eIDAS regulation recognises simple, advanced and qualified electronic signatures; only a qualified signature is automatically equivalent to a handwritten one in every member state. Exceptions exist for things like wills and some court and property documents.
Which one do I need?
If someone asks you to sign a PDF, lease or offer letter and return it, an electronic signature is almost always what they want. If a form specifically says “digitally signed”, mentions a certificate, or comes from a tax authority or court portal, you need a certificate-based digital signature.