Digital signatures vs e-signatures

People use "digital signature" and "electronic signature" interchangeably, but they mean two quite different things. The difference is about proof.

Electronic signature (e-signature)

An e-signature is any mark showing intent to sign — a drawn scribble, a typed name, a checkbox "I agree." It's what most people add when they sign a PDF. It's legally valid for the vast majority of agreements, but on its own it doesn't cryptographically prove who signed or that the document wasn't altered afterward.

Digital signature (cryptographic)

A digital signature uses public-key cryptography and a certificate from a trusted authority. When you sign, the tool computes a cryptographic hash of the document and encrypts it with your private key. Anyone can verify, using your public certificate, two things:

• Authenticity — the document was signed by the holder of that certificate.
• Integrity — not a single byte has changed since signing; any edit breaks the signature.

Which do you need?

• Everyday agreements, forms, approvals: an e-signature is fine and fast.
• Regulated, high-value, or tamper-evident documents: a certificate-based digital signature provides real cryptographic assurance.

Both have their place. For most people signing a lease or an invoice, a clean e-signature does the job — just remember to flatten the file so the content is locked.